two version of R2R are here HEAD master

1 files changed, 3593 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/numpy/core/tests/test_numeric.py b/.venv/lib/python3.12/site-packages/numpy/core/tests/test_numeric.py
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+++ b/.venv/lib/python3.12/site-packages/numpy/core/tests/test_numeric.py
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+import sys
+import warnings
+import itertools
+import platform
+import pytest
+import math
+from decimal import Decimal
+
+import numpy as np
+from numpy.core import umath
+from numpy.random import rand, randint, randn
+from numpy.testing import (
+    assert_, assert_equal, assert_raises, assert_raises_regex,
+    assert_array_equal, assert_almost_equal, assert_array_almost_equal,
+    assert_warns, assert_array_max_ulp, HAS_REFCOUNT, IS_WASM
+    )
+from numpy.core._rational_tests import rational
+
+from hypothesis import given, strategies as st
+from hypothesis.extra import numpy as hynp
+
+
+class TestResize:
+    def test_copies(self):
+        A = np.array([[1, 2], [3, 4]])
+        Ar1 = np.array([[1, 2, 3, 4], [1, 2, 3, 4]])
+        assert_equal(np.resize(A, (2, 4)), Ar1)
+
+        Ar2 = np.array([[1, 2], [3, 4], [1, 2], [3, 4]])
+        assert_equal(np.resize(A, (4, 2)), Ar2)
+
+        Ar3 = np.array([[1, 2, 3], [4, 1, 2], [3, 4, 1], [2, 3, 4]])
+        assert_equal(np.resize(A, (4, 3)), Ar3)
+
+    def test_repeats(self):
+        A = np.array([1, 2, 3])
+        Ar1 = np.array([[1, 2, 3, 1], [2, 3, 1, 2]])
+        assert_equal(np.resize(A, (2, 4)), Ar1)
+
+        Ar2 = np.array([[1, 2], [3, 1], [2, 3], [1, 2]])
+        assert_equal(np.resize(A, (4, 2)), Ar2)
+
+        Ar3 = np.array([[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]])
+        assert_equal(np.resize(A, (4, 3)), Ar3)
+
+    def test_zeroresize(self):
+        A = np.array([[1, 2], [3, 4]])
+        Ar = np.resize(A, (0,))
+        assert_array_equal(Ar, np.array([]))
+        assert_equal(A.dtype, Ar.dtype)
+
+        Ar = np.resize(A, (0, 2))
+        assert_equal(Ar.shape, (0, 2))
+
+        Ar = np.resize(A, (2, 0))
+        assert_equal(Ar.shape, (2, 0))
+
+    def test_reshape_from_zero(self):
+        # See also gh-6740
+        A = np.zeros(0, dtype=[('a', np.float32)])
+        Ar = np.resize(A, (2, 1))
+        assert_array_equal(Ar, np.zeros((2, 1), Ar.dtype))
+        assert_equal(A.dtype, Ar.dtype)
+
+    def test_negative_resize(self):
+        A = np.arange(0, 10, dtype=np.float32)
+        new_shape = (-10, -1)
+        with pytest.raises(ValueError, match=r"negative"):
+            np.resize(A, new_shape=new_shape)
+
+    def test_subclass(self):
+        class MyArray(np.ndarray):
+            __array_priority__ = 1.
+
+        my_arr = np.array([1]).view(MyArray)
+        assert type(np.resize(my_arr, 5)) is MyArray
+        assert type(np.resize(my_arr, 0)) is MyArray
+
+        my_arr = np.array([]).view(MyArray)
+        assert type(np.resize(my_arr, 5)) is MyArray
+
+
+class TestNonarrayArgs:
+    # check that non-array arguments to functions wrap them in arrays
+    def test_choose(self):
+        choices = [[0, 1, 2],
+                   [3, 4, 5],
+                   [5, 6, 7]]
+        tgt = [5, 1, 5]
+        a = [2, 0, 1]
+
+        out = np.choose(a, choices)
+        assert_equal(out, tgt)
+
+    def test_clip(self):
+        arr = [-1, 5, 2, 3, 10, -4, -9]
+        out = np.clip(arr, 2, 7)
+        tgt = [2, 5, 2, 3, 7, 2, 2]
+        assert_equal(out, tgt)
+
+    def test_compress(self):
+        arr = [[0, 1, 2, 3, 4],
+               [5, 6, 7, 8, 9]]
+        tgt = [[5, 6, 7, 8, 9]]
+        out = np.compress([0, 1], arr, axis=0)
+        assert_equal(out, tgt)
+
+    def test_count_nonzero(self):
+        arr = [[0, 1, 7, 0, 0],
+               [3, 0, 0, 2, 19]]
+        tgt = np.array([2, 3])
+        out = np.count_nonzero(arr, axis=1)
+        assert_equal(out, tgt)
+
+    def test_cumproduct(self):
+        A = [[1, 2, 3], [4, 5, 6]]
+        with assert_warns(DeprecationWarning):
+            expected = np.array([1, 2, 6, 24, 120, 720])
+            assert_(np.all(np.cumproduct(A) == expected))
+
+    def test_diagonal(self):
+        a = [[0, 1, 2, 3],
+             [4, 5, 6, 7],
+             [8, 9, 10, 11]]
+        out = np.diagonal(a)
+        tgt = [0, 5, 10]
+
+        assert_equal(out, tgt)
+
+    def test_mean(self):
+        A = [[1, 2, 3], [4, 5, 6]]
+        assert_(np.mean(A) == 3.5)
+        assert_(np.all(np.mean(A, 0) == np.array([2.5, 3.5, 4.5])))
+        assert_(np.all(np.mean(A, 1) == np.array([2., 5.])))
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.filterwarnings('always', '', RuntimeWarning)
+            assert_(np.isnan(np.mean([])))
+            assert_(w[0].category is RuntimeWarning)
+
+    def test_ptp(self):
+        a = [3, 4, 5, 10, -3, -5, 6.0]
+        assert_equal(np.ptp(a, axis=0), 15.0)
+
+    def test_prod(self):
+        arr = [[1, 2, 3, 4],
+               [5, 6, 7, 9],
+               [10, 3, 4, 5]]
+        tgt = [24, 1890, 600]
+
+        assert_equal(np.prod(arr, axis=-1), tgt)
+
+    def test_ravel(self):
+        a = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]
+        tgt = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
+        assert_equal(np.ravel(a), tgt)
+
+    def test_repeat(self):
+        a = [1, 2, 3]
+        tgt = [1, 1, 2, 2, 3, 3]
+
+        out = np.repeat(a, 2)
+        assert_equal(out, tgt)
+
+    def test_reshape(self):
+        arr = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]
+        tgt = [[1, 2, 3, 4, 5, 6], [7, 8, 9, 10, 11, 12]]
+        assert_equal(np.reshape(arr, (2, 6)), tgt)
+
+    def test_round(self):
+        arr = [1.56, 72.54, 6.35, 3.25]
+        tgt = [1.6, 72.5, 6.4, 3.2]
+        assert_equal(np.around(arr, decimals=1), tgt)
+        s = np.float64(1.)
+        assert_(isinstance(s.round(), np.float64))
+        assert_equal(s.round(), 1.)
+
+    @pytest.mark.parametrize('dtype', [
+        np.int8, np.int16, np.int32, np.int64,
+        np.uint8, np.uint16, np.uint32, np.uint64,
+        np.float16, np.float32, np.float64,
+    ])
+    def test_dunder_round(self, dtype):
+        s = dtype(1)
+        assert_(isinstance(round(s), int))
+        assert_(isinstance(round(s, None), int))
+        assert_(isinstance(round(s, ndigits=None), int))
+        assert_equal(round(s), 1)
+        assert_equal(round(s, None), 1)
+        assert_equal(round(s, ndigits=None), 1)
+
+    @pytest.mark.parametrize('val, ndigits', [
+        pytest.param(2**31 - 1, -1,
+            marks=pytest.mark.xfail(reason="Out of range of int32")
+        ),
+        (2**31 - 1, 1-math.ceil(math.log10(2**31 - 1))),
+        (2**31 - 1, -math.ceil(math.log10(2**31 - 1)))
+    ])
+    def test_dunder_round_edgecases(self, val, ndigits):
+        assert_equal(round(val, ndigits), round(np.int32(val), ndigits))
+
+    def test_dunder_round_accuracy(self):
+        f = np.float64(5.1 * 10**73)
+        assert_(isinstance(round(f, -73), np.float64))
+        assert_array_max_ulp(round(f, -73), 5.0 * 10**73)
+        assert_(isinstance(round(f, ndigits=-73), np.float64))
+        assert_array_max_ulp(round(f, ndigits=-73), 5.0 * 10**73)
+
+        i = np.int64(501)
+        assert_(isinstance(round(i, -2), np.int64))
+        assert_array_max_ulp(round(i, -2), 500)
+        assert_(isinstance(round(i, ndigits=-2), np.int64))
+        assert_array_max_ulp(round(i, ndigits=-2), 500)
+
+    @pytest.mark.xfail(raises=AssertionError, reason="gh-15896")
+    def test_round_py_consistency(self):
+        f = 5.1 * 10**73
+        assert_equal(round(np.float64(f), -73), round(f, -73))
+
+    def test_searchsorted(self):
+        arr = [-8, -5, -1, 3, 6, 10]
+        out = np.searchsorted(arr, 0)
+        assert_equal(out, 3)
+
+    def test_size(self):
+        A = [[1, 2, 3], [4, 5, 6]]
+        assert_(np.size(A) == 6)
+        assert_(np.size(A, 0) == 2)
+        assert_(np.size(A, 1) == 3)
+
+    def test_squeeze(self):
+        A = [[[1, 1, 1], [2, 2, 2], [3, 3, 3]]]
+        assert_equal(np.squeeze(A).shape, (3, 3))
+        assert_equal(np.squeeze(np.zeros((1, 3, 1))).shape, (3,))
+        assert_equal(np.squeeze(np.zeros((1, 3, 1)), axis=0).shape, (3, 1))
+        assert_equal(np.squeeze(np.zeros((1, 3, 1)), axis=-1).shape, (1, 3))
+        assert_equal(np.squeeze(np.zeros((1, 3, 1)), axis=2).shape, (1, 3))
+        assert_equal(np.squeeze([np.zeros((3, 1))]).shape, (3,))
+        assert_equal(np.squeeze([np.zeros((3, 1))], axis=0).shape, (3, 1))
+        assert_equal(np.squeeze([np.zeros((3, 1))], axis=2).shape, (1, 3))
+        assert_equal(np.squeeze([np.zeros((3, 1))], axis=-1).shape, (1, 3))
+
+    def test_std(self):
+        A = [[1, 2, 3], [4, 5, 6]]
+        assert_almost_equal(np.std(A), 1.707825127659933)
+        assert_almost_equal(np.std(A, 0), np.array([1.5, 1.5, 1.5]))
+        assert_almost_equal(np.std(A, 1), np.array([0.81649658, 0.81649658]))
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.filterwarnings('always', '', RuntimeWarning)
+            assert_(np.isnan(np.std([])))
+            assert_(w[0].category is RuntimeWarning)
+
+    def test_swapaxes(self):
+        tgt = [[[0, 4], [2, 6]], [[1, 5], [3, 7]]]
+        a = [[[0, 1], [2, 3]], [[4, 5], [6, 7]]]
+        out = np.swapaxes(a, 0, 2)
+        assert_equal(out, tgt)
+
+    def test_sum(self):
+        m = [[1, 2, 3],
+             [4, 5, 6],
+             [7, 8, 9]]
+        tgt = [[6], [15], [24]]
+        out = np.sum(m, axis=1, keepdims=True)
+
+        assert_equal(tgt, out)
+
+    def test_take(self):
+        tgt = [2, 3, 5]
+        indices = [1, 2, 4]
+        a = [1, 2, 3, 4, 5]
+
+        out = np.take(a, indices)
+        assert_equal(out, tgt)
+
+    def test_trace(self):
+        c = [[1, 2], [3, 4], [5, 6]]
+        assert_equal(np.trace(c), 5)
+
+    def test_transpose(self):
+        arr = [[1, 2], [3, 4], [5, 6]]
+        tgt = [[1, 3, 5], [2, 4, 6]]
+        assert_equal(np.transpose(arr, (1, 0)), tgt)
+
+    def test_var(self):
+        A = [[1, 2, 3], [4, 5, 6]]
+        assert_almost_equal(np.var(A), 2.9166666666666665)
+        assert_almost_equal(np.var(A, 0), np.array([2.25, 2.25, 2.25]))
+        assert_almost_equal(np.var(A, 1), np.array([0.66666667, 0.66666667]))
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.filterwarnings('always', '', RuntimeWarning)
+            assert_(np.isnan(np.var([])))
+            assert_(w[0].category is RuntimeWarning)
+
+        B = np.array([None, 0])
+        B[0] = 1j
+        assert_almost_equal(np.var(B), 0.25)
+
+
+class TestIsscalar:
+    def test_isscalar(self):
+        assert_(np.isscalar(3.1))
+        assert_(np.isscalar(np.int16(12345)))
+        assert_(np.isscalar(False))
+        assert_(np.isscalar('numpy'))
+        assert_(not np.isscalar([3.1]))
+        assert_(not np.isscalar(None))
+
+        # PEP 3141
+        from fractions import Fraction
+        assert_(np.isscalar(Fraction(5, 17)))
+        from numbers import Number
+        assert_(np.isscalar(Number()))
+
+
+class TestBoolScalar:
+    def test_logical(self):
+        f = np.False_
+        t = np.True_
+        s = "xyz"
+        assert_((t and s) is s)
+        assert_((f and s) is f)
+
+    def test_bitwise_or(self):
+        f = np.False_
+        t = np.True_
+        assert_((t | t) is t)
+        assert_((f | t) is t)
+        assert_((t | f) is t)
+        assert_((f | f) is f)
+
+    def test_bitwise_and(self):
+        f = np.False_
+        t = np.True_
+        assert_((t & t) is t)
+        assert_((f & t) is f)
+        assert_((t & f) is f)
+        assert_((f & f) is f)
+
+    def test_bitwise_xor(self):
+        f = np.False_
+        t = np.True_
+        assert_((t ^ t) is f)
+        assert_((f ^ t) is t)
+        assert_((t ^ f) is t)
+        assert_((f ^ f) is f)
+
+
+class TestBoolArray:
+    def setup_method(self):
+        # offset for simd tests
+        self.t = np.array([True] * 41, dtype=bool)[1::]
+        self.f = np.array([False] * 41, dtype=bool)[1::]
+        self.o = np.array([False] * 42, dtype=bool)[2::]
+        self.nm = self.f.copy()
+        self.im = self.t.copy()
+        self.nm[3] = True
+        self.nm[-2] = True
+        self.im[3] = False
+        self.im[-2] = False
+
+    def test_all_any(self):
+        assert_(self.t.all())
+        assert_(self.t.any())
+        assert_(not self.f.all())
+        assert_(not self.f.any())
+        assert_(self.nm.any())
+        assert_(self.im.any())
+        assert_(not self.nm.all())
+        assert_(not self.im.all())
+        # check bad element in all positions
+        for i in range(256 - 7):
+            d = np.array([False] * 256, dtype=bool)[7::]
+            d[i] = True
+            assert_(np.any(d))
+            e = np.array([True] * 256, dtype=bool)[7::]
+            e[i] = False
+            assert_(not np.all(e))
+            assert_array_equal(e, ~d)
+        # big array test for blocked libc loops
+        for i in list(range(9, 6000, 507)) + [7764, 90021, -10]:
+            d = np.array([False] * 100043, dtype=bool)
+            d[i] = True
+            assert_(np.any(d), msg="%r" % i)
+            e = np.array([True] * 100043, dtype=bool)
+            e[i] = False
+            assert_(not np.all(e), msg="%r" % i)
+
+    def test_logical_not_abs(self):
+        assert_array_equal(~self.t, self.f)
+        assert_array_equal(np.abs(~self.t), self.f)
+        assert_array_equal(np.abs(~self.f), self.t)
+        assert_array_equal(np.abs(self.f), self.f)
+        assert_array_equal(~np.abs(self.f), self.t)
+        assert_array_equal(~np.abs(self.t), self.f)
+        assert_array_equal(np.abs(~self.nm), self.im)
+        np.logical_not(self.t, out=self.o)
+        assert_array_equal(self.o, self.f)
+        np.abs(self.t, out=self.o)
+        assert_array_equal(self.o, self.t)
+
+    def test_logical_and_or_xor(self):
+        assert_array_equal(self.t | self.t, self.t)
+        assert_array_equal(self.f | self.f, self.f)
+        assert_array_equal(self.t | self.f, self.t)
+        assert_array_equal(self.f | self.t, self.t)
+        np.logical_or(self.t, self.t, out=self.o)
+        assert_array_equal(self.o, self.t)
+        assert_array_equal(self.t & self.t, self.t)
+        assert_array_equal(self.f & self.f, self.f)
+        assert_array_equal(self.t & self.f, self.f)
+        assert_array_equal(self.f & self.t, self.f)
+        np.logical_and(self.t, self.t, out=self.o)
+        assert_array_equal(self.o, self.t)
+        assert_array_equal(self.t ^ self.t, self.f)
+        assert_array_equal(self.f ^ self.f, self.f)
+        assert_array_equal(self.t ^ self.f, self.t)
+        assert_array_equal(self.f ^ self.t, self.t)
+        np.logical_xor(self.t, self.t, out=self.o)
+        assert_array_equal(self.o, self.f)
+
+        assert_array_equal(self.nm & self.t, self.nm)
+        assert_array_equal(self.im & self.f, False)
+        assert_array_equal(self.nm & True, self.nm)
+        assert_array_equal(self.im & False, self.f)
+        assert_array_equal(self.nm | self.t, self.t)
+        assert_array_equal(self.im | self.f, self.im)
+        assert_array_equal(self.nm | True, self.t)
+        assert_array_equal(self.im | False, self.im)
+        assert_array_equal(self.nm ^ self.t, self.im)
+        assert_array_equal(self.im ^ self.f, self.im)
+        assert_array_equal(self.nm ^ True, self.im)
+        assert_array_equal(self.im ^ False, self.im)
+
+
+class TestBoolCmp:
+    def setup_method(self):
+        self.f = np.ones(256, dtype=np.float32)
+        self.ef = np.ones(self.f.size, dtype=bool)
+        self.d = np.ones(128, dtype=np.float64)
+        self.ed = np.ones(self.d.size, dtype=bool)
+        # generate values for all permutation of 256bit simd vectors
+        s = 0
+        for i in range(32):
+            self.f[s:s+8] = [i & 2**x for x in range(8)]
+            self.ef[s:s+8] = [(i & 2**x) != 0 for x in range(8)]
+            s += 8
+        s = 0
+        for i in range(16):
+            self.d[s:s+4] = [i & 2**x for x in range(4)]
+            self.ed[s:s+4] = [(i & 2**x) != 0 for x in range(4)]
+            s += 4
+
+        self.nf = self.f.copy()
+        self.nd = self.d.copy()
+        self.nf[self.ef] = np.nan
+        self.nd[self.ed] = np.nan
+
+        self.inff = self.f.copy()
+        self.infd = self.d.copy()
+        self.inff[::3][self.ef[::3]] = np.inf
+        self.infd[::3][self.ed[::3]] = np.inf
+        self.inff[1::3][self.ef[1::3]] = -np.inf
+        self.infd[1::3][self.ed[1::3]] = -np.inf
+        self.inff[2::3][self.ef[2::3]] = np.nan
+        self.infd[2::3][self.ed[2::3]] = np.nan
+        self.efnonan = self.ef.copy()
+        self.efnonan[2::3] = False
+        self.ednonan = self.ed.copy()
+        self.ednonan[2::3] = False
+
+        self.signf = self.f.copy()
+        self.signd = self.d.copy()
+        self.signf[self.ef] *= -1.
+        self.signd[self.ed] *= -1.
+        self.signf[1::6][self.ef[1::6]] = -np.inf
+        self.signd[1::6][self.ed[1::6]] = -np.inf
+        # On RISC-V, many operations that produce NaNs, such as converting
+        # a -NaN from f64 to f32, return a canonical NaN.  The canonical
+        # NaNs are always positive.  See section 11.3 NaN Generation and
+        # Propagation of the RISC-V Unprivileged ISA for more details.
+        # We disable the float32 sign test on riscv64 for -np.nan as the sign
+        # of the NaN will be lost when it's converted to a float32.
+        if platform.processor() != 'riscv64':
+            self.signf[3::6][self.ef[3::6]] = -np.nan
+        self.signd[3::6][self.ed[3::6]] = -np.nan
+        self.signf[4::6][self.ef[4::6]] = -0.
+        self.signd[4::6][self.ed[4::6]] = -0.
+
+    def test_float(self):
+        # offset for alignment test
+        for i in range(4):
+            assert_array_equal(self.f[i:] > 0, self.ef[i:])
+            assert_array_equal(self.f[i:] - 1 >= 0, self.ef[i:])
+            assert_array_equal(self.f[i:] == 0, ~self.ef[i:])
+            assert_array_equal(-self.f[i:] < 0, self.ef[i:])
+            assert_array_equal(-self.f[i:] + 1 <= 0, self.ef[i:])
+            r = self.f[i:] != 0
+            assert_array_equal(r, self.ef[i:])
+            r2 = self.f[i:] != np.zeros_like(self.f[i:])
+            r3 = 0 != self.f[i:]
+            assert_array_equal(r, r2)
+            assert_array_equal(r, r3)
+            # check bool == 0x1
+            assert_array_equal(r.view(np.int8), r.astype(np.int8))
+            assert_array_equal(r2.view(np.int8), r2.astype(np.int8))
+            assert_array_equal(r3.view(np.int8), r3.astype(np.int8))
+
+            # isnan on amd64 takes the same code path
+            assert_array_equal(np.isnan(self.nf[i:]), self.ef[i:])
+            assert_array_equal(np.isfinite(self.nf[i:]), ~self.ef[i:])
+            assert_array_equal(np.isfinite(self.inff[i:]), ~self.ef[i:])
+            assert_array_equal(np.isinf(self.inff[i:]), self.efnonan[i:])
+            assert_array_equal(np.signbit(self.signf[i:]), self.ef[i:])
+
+    def test_double(self):
+        # offset for alignment test
+        for i in range(2):
+            assert_array_equal(self.d[i:] > 0, self.ed[i:])
+            assert_array_equal(self.d[i:] - 1 >= 0, self.ed[i:])
+            assert_array_equal(self.d[i:] == 0, ~self.ed[i:])
+            assert_array_equal(-self.d[i:] < 0, self.ed[i:])
+            assert_array_equal(-self.d[i:] + 1 <= 0, self.ed[i:])
+            r = self.d[i:] != 0
+            assert_array_equal(r, self.ed[i:])
+            r2 = self.d[i:] != np.zeros_like(self.d[i:])
+            r3 = 0 != self.d[i:]
+            assert_array_equal(r, r2)
+            assert_array_equal(r, r3)
+            # check bool == 0x1
+            assert_array_equal(r.view(np.int8), r.astype(np.int8))
+            assert_array_equal(r2.view(np.int8), r2.astype(np.int8))
+            assert_array_equal(r3.view(np.int8), r3.astype(np.int8))
+
+            # isnan on amd64 takes the same code path
+            assert_array_equal(np.isnan(self.nd[i:]), self.ed[i:])
+            assert_array_equal(np.isfinite(self.nd[i:]), ~self.ed[i:])
+            assert_array_equal(np.isfinite(self.infd[i:]), ~self.ed[i:])
+            assert_array_equal(np.isinf(self.infd[i:]), self.ednonan[i:])
+            assert_array_equal(np.signbit(self.signd[i:]), self.ed[i:])
+
+
+class TestSeterr:
+    def test_default(self):
+        err = np.geterr()
+        assert_equal(err,
+                     dict(divide='warn',
+                          invalid='warn',
+                          over='warn',
+                          under='ignore')
+                     )
+
+    def test_set(self):
+        with np.errstate():
+            err = np.seterr()
+            old = np.seterr(divide='print')
+            assert_(err == old)
+            new = np.seterr()
+            assert_(new['divide'] == 'print')
+            np.seterr(over='raise')
+            assert_(np.geterr()['over'] == 'raise')
+            assert_(new['divide'] == 'print')
+            np.seterr(**old)
+            assert_(np.geterr() == old)
+
+    @pytest.mark.skipif(IS_WASM, reason="no wasm fp exception support")
+    @pytest.mark.skipif(platform.machine() == "armv5tel", reason="See gh-413.")
+    def test_divide_err(self):
+        with np.errstate(divide='raise'):
+            with assert_raises(FloatingPointError):
+                np.array([1.]) / np.array([0.])
+
+            np.seterr(divide='ignore')
+            np.array([1.]) / np.array([0.])
+
+    @pytest.mark.skipif(IS_WASM, reason="no wasm fp exception support")
+    def test_errobj(self):
+        olderrobj = np.geterrobj()
+        self.called = 0
+        try:
+            with warnings.catch_warnings(record=True) as w:
+                warnings.simplefilter("always")
+                with np.errstate(divide='warn'):
+                    np.seterrobj([20000, 1, None])
+                    np.array([1.]) / np.array([0.])
+                    assert_equal(len(w), 1)
+
+            def log_err(*args):
+                self.called += 1
+                extobj_err = args
+                assert_(len(extobj_err) == 2)
+                assert_("divide" in extobj_err[0])
+
+            with np.errstate(divide='ignore'):
+                np.seterrobj([20000, 3, log_err])
+                np.array([1.]) / np.array([0.])
+            assert_equal(self.called, 1)
+
+            np.seterrobj(olderrobj)
+            with np.errstate(divide='ignore'):
+                np.divide(1., 0., extobj=[20000, 3, log_err])
+            assert_equal(self.called, 2)
+        finally:
+            np.seterrobj(olderrobj)
+            del self.called
+
+    def test_errobj_noerrmask(self):
+        # errmask = 0 has a special code path for the default
+        olderrobj = np.geterrobj()
+        try:
+            # set errobj to something non default
+            np.seterrobj([umath.UFUNC_BUFSIZE_DEFAULT,
+                         umath.ERR_DEFAULT + 1, None])
+            # call a ufunc
+            np.isnan(np.array([6]))
+            # same with the default, lots of times to get rid of possible
+            # pre-existing stack in the code
+            for i in range(10000):
+                np.seterrobj([umath.UFUNC_BUFSIZE_DEFAULT, umath.ERR_DEFAULT,
+                             None])
+            np.isnan(np.array([6]))
+        finally:
+            np.seterrobj(olderrobj)
+
+
+class TestFloatExceptions:
+    def assert_raises_fpe(self, fpeerr, flop, x, y):
+        ftype = type(x)
+        try:
+            flop(x, y)
+            assert_(False,
+                    "Type %s did not raise fpe error '%s'." % (ftype, fpeerr))
+        except FloatingPointError as exc:
+            assert_(str(exc).find(fpeerr) >= 0,
+                    "Type %s raised wrong fpe error '%s'." % (ftype, exc))
+
+    def assert_op_raises_fpe(self, fpeerr, flop, sc1, sc2):
+        # Check that fpe exception is raised.
+        #
+        # Given a floating operation `flop` and two scalar values, check that
+        # the operation raises the floating point exception specified by
+        # `fpeerr`. Tests all variants with 0-d array scalars as well.
+
+        self.assert_raises_fpe(fpeerr, flop, sc1, sc2)
+        self.assert_raises_fpe(fpeerr, flop, sc1[()], sc2)
+        self.assert_raises_fpe(fpeerr, flop, sc1, sc2[()])
+        self.assert_raises_fpe(fpeerr, flop, sc1[()], sc2[()])
+
+    # Test for all real and complex float types
+    @pytest.mark.skipif(IS_WASM, reason="no wasm fp exception support")
+    @pytest.mark.parametrize("typecode", np.typecodes["AllFloat"])
+    def test_floating_exceptions(self, typecode):
+        if 'bsd' in sys.platform and typecode in 'gG':
+            pytest.skip(reason="Fallback impl for (c)longdouble may not raise "
+                               "FPE errors as expected on BSD OSes, "
+                               "see gh-24876, gh-23379")
+
+        # Test basic arithmetic function errors
+        with np.errstate(all='raise'):
+            ftype = np.obj2sctype(typecode)
+            if np.dtype(ftype).kind == 'f':
+                # Get some extreme values for the type
+                fi = np.finfo(ftype)
+                ft_tiny = fi._machar.tiny
+                ft_max = fi.max
+                ft_eps = fi.eps
+                underflow = 'underflow'
+                divbyzero = 'divide by zero'
+            else:
+                # 'c', complex, corresponding real dtype
+                rtype = type(ftype(0).real)
+                fi = np.finfo(rtype)
+                ft_tiny = ftype(fi._machar.tiny)
+                ft_max = ftype(fi.max)
+                ft_eps = ftype(fi.eps)
+                # The complex types raise different exceptions
+                underflow = ''
+                divbyzero = ''
+            overflow = 'overflow'
+            invalid = 'invalid'
+
+            # The value of tiny for double double is NaN, so we need to
+            # pass the assert
+            if not np.isnan(ft_tiny):
+                self.assert_raises_fpe(underflow,
+                                    lambda a, b: a/b, ft_tiny, ft_max)
+                self.assert_raises_fpe(underflow,
+                                    lambda a, b: a*b, ft_tiny, ft_tiny)
+            self.assert_raises_fpe(overflow,
+                                   lambda a, b: a*b, ft_max, ftype(2))
+            self.assert_raises_fpe(overflow,
+                                   lambda a, b: a/b, ft_max, ftype(0.5))
+            self.assert_raises_fpe(overflow,
+                                   lambda a, b: a+b, ft_max, ft_max*ft_eps)
+            self.assert_raises_fpe(overflow,
+                                   lambda a, b: a-b, -ft_max, ft_max*ft_eps)
+            self.assert_raises_fpe(overflow,
+                                   np.power, ftype(2), ftype(2**fi.nexp))
+            self.assert_raises_fpe(divbyzero,
+                                   lambda a, b: a/b, ftype(1), ftype(0))
+            self.assert_raises_fpe(
+                invalid, lambda a, b: a/b, ftype(np.inf), ftype(np.inf)
+            )
+            self.assert_raises_fpe(invalid,
+                                   lambda a, b: a/b, ftype(0), ftype(0))
+            self.assert_raises_fpe(
+                invalid, lambda a, b: a-b, ftype(np.inf), ftype(np.inf)
+            )
+            self.assert_raises_fpe(
+                invalid, lambda a, b: a+b, ftype(np.inf), ftype(-np.inf)
+            )
+            self.assert_raises_fpe(invalid,
+                                   lambda a, b: a*b, ftype(0), ftype(np.inf))
+
+    @pytest.mark.skipif(IS_WASM, reason="no wasm fp exception support")
+    def test_warnings(self):
+        # test warning code path
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+            with np.errstate(all="warn"):
+                np.divide(1, 0.)
+                assert_equal(len(w), 1)
+                assert_("divide by zero" in str(w[0].message))
+                np.array(1e300) * np.array(1e300)
+                assert_equal(len(w), 2)
+                assert_("overflow" in str(w[-1].message))
+                np.array(np.inf) - np.array(np.inf)
+                assert_equal(len(w), 3)
+                assert_("invalid value" in str(w[-1].message))
+                np.array(1e-300) * np.array(1e-300)
+                assert_equal(len(w), 4)
+                assert_("underflow" in str(w[-1].message))
+
+
+class TestTypes:
+    def check_promotion_cases(self, promote_func):
+        # tests that the scalars get coerced correctly.
+        b = np.bool_(0)
+        i8, i16, i32, i64 = np.int8(0), np.int16(0), np.int32(0), np.int64(0)
+        u8, u16, u32, u64 = np.uint8(0), np.uint16(0), np.uint32(0), np.uint64(0)
+        f32, f64, fld = np.float32(0), np.float64(0), np.longdouble(0)
+        c64, c128, cld = np.complex64(0), np.complex128(0), np.clongdouble(0)
+
+        # coercion within the same kind
+        assert_equal(promote_func(i8, i16), np.dtype(np.int16))
+        assert_equal(promote_func(i32, i8), np.dtype(np.int32))
+        assert_equal(promote_func(i16, i64), np.dtype(np.int64))
+        assert_equal(promote_func(u8, u32), np.dtype(np.uint32))
+        assert_equal(promote_func(f32, f64), np.dtype(np.float64))
+        assert_equal(promote_func(fld, f32), np.dtype(np.longdouble))
+        assert_equal(promote_func(f64, fld), np.dtype(np.longdouble))
+        assert_equal(promote_func(c128, c64), np.dtype(np.complex128))
+        assert_equal(promote_func(cld, c128), np.dtype(np.clongdouble))
+        assert_equal(promote_func(c64, fld), np.dtype(np.clongdouble))
+
+        # coercion between kinds
+        assert_equal(promote_func(b, i32), np.dtype(np.int32))
+        assert_equal(promote_func(b, u8), np.dtype(np.uint8))
+        assert_equal(promote_func(i8, u8), np.dtype(np.int16))
+        assert_equal(promote_func(u8, i32), np.dtype(np.int32))
+        assert_equal(promote_func(i64, u32), np.dtype(np.int64))
+        assert_equal(promote_func(u64, i32), np.dtype(np.float64))
+        assert_equal(promote_func(i32, f32), np.dtype(np.float64))
+        assert_equal(promote_func(i64, f32), np.dtype(np.float64))
+        assert_equal(promote_func(f32, i16), np.dtype(np.float32))
+        assert_equal(promote_func(f32, u32), np.dtype(np.float64))
+        assert_equal(promote_func(f32, c64), np.dtype(np.complex64))
+        assert_equal(promote_func(c128, f32), np.dtype(np.complex128))
+        assert_equal(promote_func(cld, f64), np.dtype(np.clongdouble))
+
+        # coercion between scalars and 1-D arrays
+        assert_equal(promote_func(np.array([b]), i8), np.dtype(np.int8))
+        assert_equal(promote_func(np.array([b]), u8), np.dtype(np.uint8))
+        assert_equal(promote_func(np.array([b]), i32), np.dtype(np.int32))
+        assert_equal(promote_func(np.array([b]), u32), np.dtype(np.uint32))
+        assert_equal(promote_func(np.array([i8]), i64), np.dtype(np.int8))
+        assert_equal(promote_func(u64, np.array([i32])), np.dtype(np.int32))
+        assert_equal(promote_func(i64, np.array([u32])), np.dtype(np.uint32))
+        assert_equal(promote_func(np.int32(-1), np.array([u64])),
+                     np.dtype(np.float64))
+        assert_equal(promote_func(f64, np.array([f32])), np.dtype(np.float32))
+        assert_equal(promote_func(fld, np.array([f32])), np.dtype(np.float32))
+        assert_equal(promote_func(np.array([f64]), fld), np.dtype(np.float64))
+        assert_equal(promote_func(fld, np.array([c64])),
+                     np.dtype(np.complex64))
+        assert_equal(promote_func(c64, np.array([f64])),
+                     np.dtype(np.complex128))
+        assert_equal(promote_func(np.complex64(3j), np.array([f64])),
+                     np.dtype(np.complex128))
+
+        # coercion between scalars and 1-D arrays, where
+        # the scalar has greater kind than the array
+        assert_equal(promote_func(np.array([b]), f64), np.dtype(np.float64))
+        assert_equal(promote_func(np.array([b]), i64), np.dtype(np.int64))
+        assert_equal(promote_func(np.array([b]), u64), np.dtype(np.uint64))
+        assert_equal(promote_func(np.array([i8]), f64), np.dtype(np.float64))
+        assert_equal(promote_func(np.array([u16]), f64), np.dtype(np.float64))
+
+        # uint and int are treated as the same "kind" for
+        # the purposes of array-scalar promotion.
+        assert_equal(promote_func(np.array([u16]), i32), np.dtype(np.uint16))
+
+        # float and complex are treated as the same "kind" for
+        # the purposes of array-scalar promotion, so that you can do
+        # (0j + float32array) to get a complex64 array instead of
+        # a complex128 array.
+        assert_equal(promote_func(np.array([f32]), c128),
+                     np.dtype(np.complex64))
+
+    def test_coercion(self):
+        def res_type(a, b):
+            return np.add(a, b).dtype
+
+        self.check_promotion_cases(res_type)
+
+        # Use-case: float/complex scalar * bool/int8 array
+        #           shouldn't narrow the float/complex type
+        for a in [np.array([True, False]), np.array([-3, 12], dtype=np.int8)]:
+            b = 1.234 * a
+            assert_equal(b.dtype, np.dtype('f8'), "array type %s" % a.dtype)
+            b = np.longdouble(1.234) * a
+            assert_equal(b.dtype, np.dtype(np.longdouble),
+                         "array type %s" % a.dtype)
+            b = np.float64(1.234) * a
+            assert_equal(b.dtype, np.dtype('f8'), "array type %s" % a.dtype)
+            b = np.float32(1.234) * a
+            assert_equal(b.dtype, np.dtype('f4'), "array type %s" % a.dtype)
+            b = np.float16(1.234) * a
+            assert_equal(b.dtype, np.dtype('f2'), "array type %s" % a.dtype)
+
+            b = 1.234j * a
+            assert_equal(b.dtype, np.dtype('c16'), "array type %s" % a.dtype)
+            b = np.clongdouble(1.234j) * a
+            assert_equal(b.dtype, np.dtype(np.clongdouble),
+                         "array type %s" % a.dtype)
+            b = np.complex128(1.234j) * a
+            assert_equal(b.dtype, np.dtype('c16'), "array type %s" % a.dtype)
+            b = np.complex64(1.234j) * a
+            assert_equal(b.dtype, np.dtype('c8'), "array type %s" % a.dtype)
+
+        # The following use-case is problematic, and to resolve its
+        # tricky side-effects requires more changes.
+        #
+        # Use-case: (1-t)*a, where 't' is a boolean array and 'a' is
+        #            a float32, shouldn't promote to float64
+        #
+        # a = np.array([1.0, 1.5], dtype=np.float32)
+        # t = np.array([True, False])
+        # b = t*a
+        # assert_equal(b, [1.0, 0.0])
+        # assert_equal(b.dtype, np.dtype('f4'))
+        # b = (1-t)*a
+        # assert_equal(b, [0.0, 1.5])
+        # assert_equal(b.dtype, np.dtype('f4'))
+        #
+        # Probably ~t (bitwise negation) is more proper to use here,
+        # but this is arguably less intuitive to understand at a glance, and
+        # would fail if 't' is actually an integer array instead of boolean:
+        #
+        # b = (~t)*a
+        # assert_equal(b, [0.0, 1.5])
+        # assert_equal(b.dtype, np.dtype('f4'))
+
+    def test_result_type(self):
+        self.check_promotion_cases(np.result_type)
+        assert_(np.result_type(None) == np.dtype(None))
+
+    def test_promote_types_endian(self):
+        # promote_types should always return native-endian types
+        assert_equal(np.promote_types('<i8', '<i8'), np.dtype('i8'))
+        assert_equal(np.promote_types('>i8', '>i8'), np.dtype('i8'))
+
+        assert_equal(np.promote_types('>i8', '>U16'), np.dtype('U21'))
+        assert_equal(np.promote_types('<i8', '<U16'), np.dtype('U21'))
+        assert_equal(np.promote_types('>U16', '>i8'), np.dtype('U21'))
+        assert_equal(np.promote_types('<U16', '<i8'), np.dtype('U21'))
+
+        assert_equal(np.promote_types('<S5', '<U8'), np.dtype('U8'))
+        assert_equal(np.promote_types('>S5', '>U8'), np.dtype('U8'))
+        assert_equal(np.promote_types('<U8', '<S5'), np.dtype('U8'))
+        assert_equal(np.promote_types('>U8', '>S5'), np.dtype('U8'))
+        assert_equal(np.promote_types('<U5', '<U8'), np.dtype('U8'))
+        assert_equal(np.promote_types('>U8', '>U5'), np.dtype('U8'))
+
+        assert_equal(np.promote_types('<M8', '<M8'), np.dtype('M8'))
+        assert_equal(np.promote_types('>M8', '>M8'), np.dtype('M8'))
+        assert_equal(np.promote_types('<m8', '<m8'), np.dtype('m8'))
+        assert_equal(np.promote_types('>m8', '>m8'), np.dtype('m8'))
+
+    def test_can_cast_and_promote_usertypes(self):
+        # The rational type defines safe casting for signed integers,
+        # boolean. Rational itself *does* cast safely to double.
+        # (rational does not actually cast to all signed integers, e.g.
+        # int64 can be both long and longlong and it registers only the first)
+        valid_types = ["int8", "int16", "int32", "int64", "bool"]
+        invalid_types = "BHILQP" + "FDG" + "mM" + "f" + "V"
+
+        rational_dt = np.dtype(rational)
+        for numpy_dtype in valid_types:
+            numpy_dtype = np.dtype(numpy_dtype)
+            assert np.can_cast(numpy_dtype, rational_dt)
+            assert np.promote_types(numpy_dtype, rational_dt) is rational_dt
+
+        for numpy_dtype in invalid_types:
+            numpy_dtype = np.dtype(numpy_dtype)
+            assert not np.can_cast(numpy_dtype, rational_dt)
+            with pytest.raises(TypeError):
+                np.promote_types(numpy_dtype, rational_dt)
+
+        double_dt = np.dtype("double")
+        assert np.can_cast(rational_dt, double_dt)
+        assert np.promote_types(double_dt, rational_dt) is double_dt
+
+    @pytest.mark.parametrize("swap", ["", "swap"])
+    @pytest.mark.parametrize("string_dtype", ["U", "S"])
+    def test_promote_types_strings(self, swap, string_dtype):
+        if swap == "swap":
+            promote_types = lambda a, b: np.promote_types(b, a)
+        else:
+            promote_types = np.promote_types
+
+        S = string_dtype
+
+        # Promote numeric with unsized string:
+        assert_equal(promote_types('bool', S), np.dtype(S+'5'))
+        assert_equal(promote_types('b', S), np.dtype(S+'4'))
+        assert_equal(promote_types('u1', S), np.dtype(S+'3'))
+        assert_equal(promote_types('u2', S), np.dtype(S+'5'))
+        assert_equal(promote_types('u4', S), np.dtype(S+'10'))
+        assert_equal(promote_types('u8', S), np.dtype(S+'20'))
+        assert_equal(promote_types('i1', S), np.dtype(S+'4'))
+        assert_equal(promote_types('i2', S), np.dtype(S+'6'))
+        assert_equal(promote_types('i4', S), np.dtype(S+'11'))
+        assert_equal(promote_types('i8', S), np.dtype(S+'21'))
+        # Promote numeric with sized string:
+        assert_equal(promote_types('bool', S+'1'), np.dtype(S+'5'))
+        assert_equal(promote_types('bool', S+'30'), np.dtype(S+'30'))
+        assert_equal(promote_types('b', S+'1'), np.dtype(S+'4'))
+        assert_equal(promote_types('b', S+'30'), np.dtype(S+'30'))
+        assert_equal(promote_types('u1', S+'1'), np.dtype(S+'3'))
+        assert_equal(promote_types('u1', S+'30'), np.dtype(S+'30'))
+        assert_equal(promote_types('u2', S+'1'), np.dtype(S+'5'))
+        assert_equal(promote_types('u2', S+'30'), np.dtype(S+'30'))
+        assert_equal(promote_types('u4', S+'1'), np.dtype(S+'10'))
+        assert_equal(promote_types('u4', S+'30'), np.dtype(S+'30'))
+        assert_equal(promote_types('u8', S+'1'), np.dtype(S+'20'))
+        assert_equal(promote_types('u8', S+'30'), np.dtype(S+'30'))
+        # Promote with object:
+        assert_equal(promote_types('O', S+'30'), np.dtype('O'))
+
+    @pytest.mark.parametrize(["dtype1", "dtype2"],
+            [[np.dtype("V6"), np.dtype("V10")],  # mismatch shape
+             # Mismatching names:
+             [np.dtype([("name1", "i8")]), np.dtype([("name2", "i8")])],
+            ])
+    def test_invalid_void_promotion(self, dtype1, dtype2):
+        with pytest.raises(TypeError):
+            np.promote_types(dtype1, dtype2)
+
+    @pytest.mark.parametrize(["dtype1", "dtype2"],
+            [[np.dtype("V10"), np.dtype("V10")],
+             [np.dtype([("name1", "i8")]),
+              np.dtype([("name1", np.dtype("i8").newbyteorder())])],
+             [np.dtype("i8,i8"), np.dtype("i8,>i8")],
+             [np.dtype("i8,i8"), np.dtype("i4,i4")],
+            ])
+    def test_valid_void_promotion(self, dtype1, dtype2):
+        assert np.promote_types(dtype1, dtype2) == dtype1
+
+    @pytest.mark.parametrize("dtype",
+            list(np.typecodes["All"]) +
+            ["i,i", "10i", "S3", "S100", "U3", "U100", rational])
+    def test_promote_identical_types_metadata(self, dtype):
+        # The same type passed in twice to promote types always
+        # preserves metadata
+        metadata = {1: 1}
+        dtype = np.dtype(dtype, metadata=metadata)
+
+        res = np.promote_types(dtype, dtype)
+        assert res.metadata == dtype.metadata
+
+        # byte-swapping preserves and makes the dtype native:
+        dtype = dtype.newbyteorder()
+        if dtype.isnative:
+            # The type does not have byte swapping
+            return
+
+        res = np.promote_types(dtype, dtype)
+
+        # Metadata is (currently) generally lost on byte-swapping (except for
+        # unicode.
+        if dtype.char != "U":
+            assert res.metadata is None
+        else:
+            assert res.metadata == metadata
+        assert res.isnative
+
+    @pytest.mark.slow
+    @pytest.mark.filterwarnings('ignore:Promotion of numbers:FutureWarning')
+    @pytest.mark.parametrize(["dtype1", "dtype2"],
+            itertools.product(
+                list(np.typecodes["All"]) +
+                ["i,i", "S3", "S100", "U3", "U100", rational],
+                repeat=2))
+    def test_promote_types_metadata(self, dtype1, dtype2):
+        """Metadata handling in promotion does not appear formalized
+        right now in NumPy. This test should thus be considered to
+        document behaviour, rather than test the correct definition of it.
+
+        This test is very ugly, it was useful for rewriting part of the
+        promotion, but probably should eventually be replaced/deleted
+        (i.e. when metadata handling in promotion is better defined).
+        """
+        metadata1 = {1: 1}
+        metadata2 = {2: 2}
+        dtype1 = np.dtype(dtype1, metadata=metadata1)
+        dtype2 = np.dtype(dtype2, metadata=metadata2)
+
+        try:
+            res = np.promote_types(dtype1, dtype2)
+        except TypeError:
+            # Promotion failed, this test only checks metadata
+            return
+
+        if res.char not in "USV" or res.names is not None or res.shape != ():
+            # All except string dtypes (and unstructured void) lose metadata
+            # on promotion (unless both dtypes are identical).
+            # At some point structured ones did not, but were restrictive.
+            assert res.metadata is None
+        elif res == dtype1:
+            # If one result is the result, it is usually returned unchanged:
+            assert res is dtype1
+        elif res == dtype2:
+            # dtype1 may have been cast to the same type/kind as dtype2.
+            # If the resulting dtype is identical we currently pick the cast
+            # version of dtype1, which lost the metadata:
+            if np.promote_types(dtype1, dtype2.kind) == dtype2:
+                res.metadata is None
+            else:
+                res.metadata == metadata2
+        else:
+            assert res.metadata is None
+
+        # Try again for byteswapped version
+        dtype1 = dtype1.newbyteorder()
+        assert dtype1.metadata == metadata1
+        res_bs = np.promote_types(dtype1, dtype2)
+        assert res_bs == res
+        assert res_bs.metadata == res.metadata
+
+    def test_can_cast(self):
+        assert_(np.can_cast(np.int32, np.int64))
+        assert_(np.can_cast(np.float64, complex))
+        assert_(not np.can_cast(complex, float))
+
+        assert_(np.can_cast('i8', 'f8'))
+        assert_(not np.can_cast('i8', 'f4'))
+        assert_(np.can_cast('i4', 'S11'))
+
+        assert_(np.can_cast('i8', 'i8', 'no'))
+        assert_(not np.can_cast('<i8', '>i8', 'no'))
+
+        assert_(np.can_cast('<i8', '>i8', 'equiv'))
+        assert_(not np.can_cast('<i4', '>i8', 'equiv'))
+
+        assert_(np.can_cast('<i4', '>i8', 'safe'))
+        assert_(not np.can_cast('<i8', '>i4', 'safe'))
+
+        assert_(np.can_cast('<i8', '>i4', 'same_kind'))
+        assert_(not np.can_cast('<i8', '>u4', 'same_kind'))
+
+        assert_(np.can_cast('<i8', '>u4', 'unsafe'))
+
+        assert_(np.can_cast('bool', 'S5'))
+        assert_(not np.can_cast('bool', 'S4'))
+
+        assert_(np.can_cast('b', 'S4'))
+        assert_(not np.can_cast('b', 'S3'))
+
+        assert_(np.can_cast('u1', 'S3'))
+        assert_(not np.can_cast('u1', 'S2'))
+        assert_(np.can_cast('u2', 'S5'))
+        assert_(not np.can_cast('u2', 'S4'))
+        assert_(np.can_cast('u4', 'S10'))
+        assert_(not np.can_cast('u4', 'S9'))
+        assert_(np.can_cast('u8', 'S20'))
+        assert_(not np.can_cast('u8', 'S19'))
+
+        assert_(np.can_cast('i1', 'S4'))
+        assert_(not np.can_cast('i1', 'S3'))
+        assert_(np.can_cast('i2', 'S6'))
+        assert_(not np.can_cast('i2', 'S5'))
+        assert_(np.can_cast('i4', 'S11'))
+        assert_(not np.can_cast('i4', 'S10'))
+        assert_(np.can_cast('i8', 'S21'))
+        assert_(not np.can_cast('i8', 'S20'))
+
+        assert_(np.can_cast('bool', 'S5'))
+        assert_(not np.can_cast('bool', 'S4'))
+
+        assert_(np.can_cast('b', 'U4'))
+        assert_(not np.can_cast('b', 'U3'))
+
+        assert_(np.can_cast('u1', 'U3'))
+        assert_(not np.can_cast('u1', 'U2'))
+        assert_(np.can_cast('u2', 'U5'))
+        assert_(not np.can_cast('u2', 'U4'))
+        assert_(np.can_cast('u4', 'U10'))
+        assert_(not np.can_cast('u4', 'U9'))
+        assert_(np.can_cast('u8', 'U20'))
+        assert_(not np.can_cast('u8', 'U19'))
+
+        assert_(np.can_cast('i1', 'U4'))
+        assert_(not np.can_cast('i1', 'U3'))
+        assert_(np.can_cast('i2', 'U6'))
+        assert_(not np.can_cast('i2', 'U5'))
+        assert_(np.can_cast('i4', 'U11'))
+        assert_(not np.can_cast('i4', 'U10'))
+        assert_(np.can_cast('i8', 'U21'))
+        assert_(not np.can_cast('i8', 'U20'))
+
+        assert_raises(TypeError, np.can_cast, 'i4', None)
+        assert_raises(TypeError, np.can_cast, None, 'i4')
+
+        # Also test keyword arguments
+        assert_(np.can_cast(from_=np.int32, to=np.int64))
+
+    def test_can_cast_simple_to_structured(self):
+        # Non-structured can only be cast to structured in 'unsafe' mode.
+        assert_(not np.can_cast('i4', 'i4,i4'))
+        assert_(not np.can_cast('i4', 'i4,i2'))
+        assert_(np.can_cast('i4', 'i4,i4', casting='unsafe'))
+        assert_(np.can_cast('i4', 'i4,i2', casting='unsafe'))
+        # Even if there is just a single field which is OK.
+        assert_(not np.can_cast('i2', [('f1', 'i4')]))
+        assert_(not np.can_cast('i2', [('f1', 'i4')], casting='same_kind'))
+        assert_(np.can_cast('i2', [('f1', 'i4')], casting='unsafe'))
+        # It should be the same for recursive structured or subarrays.
+        assert_(not np.can_cast('i2', [('f1', 'i4,i4')]))
+        assert_(np.can_cast('i2', [('f1', 'i4,i4')], casting='unsafe'))
+        assert_(not np.can_cast('i2', [('f1', '(2,3)i4')]))
+        assert_(np.can_cast('i2', [('f1', '(2,3)i4')], casting='unsafe'))
+
+    def test_can_cast_structured_to_simple(self):
+        # Need unsafe casting for structured to simple.
+        assert_(not np.can_cast([('f1', 'i4')], 'i4'))
+        assert_(np.can_cast([('f1', 'i4')], 'i4', casting='unsafe'))
+        assert_(np.can_cast([('f1', 'i4')], 'i2', casting='unsafe'))
+        # Since it is unclear what is being cast, multiple fields to
+        # single should not work even for unsafe casting.
+        assert_(not np.can_cast('i4,i4', 'i4', casting='unsafe'))
+        # But a single field inside a single field is OK.
+        assert_(not np.can_cast([('f1', [('x', 'i4')])], 'i4'))
+        assert_(np.can_cast([('f1', [('x', 'i4')])], 'i4', casting='unsafe'))
+        # And a subarray is fine too - it will just take the first element
+        # (arguably not very consistently; might also take the first field).
+        assert_(not np.can_cast([('f0', '(3,)i4')], 'i4'))
+        assert_(np.can_cast([('f0', '(3,)i4')], 'i4', casting='unsafe'))
+        # But a structured subarray with multiple fields should fail.
+        assert_(not np.can_cast([('f0', ('i4,i4'), (2,))], 'i4',
+                                casting='unsafe'))
+
+    def test_can_cast_values(self):
+        # gh-5917
+        for dt in np.sctypes['int'] + np.sctypes['uint']:
+            ii = np.iinfo(dt)
+            assert_(np.can_cast(ii.min, dt))
+            assert_(np.can_cast(ii.max, dt))
+            assert_(not np.can_cast(ii.min - 1, dt))
+            assert_(not np.can_cast(ii.max + 1, dt))
+
+        for dt in np.sctypes['float']:
+            fi = np.finfo(dt)
+            assert_(np.can_cast(fi.min, dt))
+            assert_(np.can_cast(fi.max, dt))
+
+
+# Custom exception class to test exception propagation in fromiter
+class NIterError(Exception):
+    pass
+
+
+class TestFromiter:
+    def makegen(self):
+        return (x**2 for x in range(24))
+
+    def test_types(self):
+        ai32 = np.fromiter(self.makegen(), np.int32)
+        ai64 = np.fromiter(self.makegen(), np.int64)
+        af = np.fromiter(self.makegen(), float)
+        assert_(ai32.dtype == np.dtype(np.int32))
+        assert_(ai64.dtype == np.dtype(np.int64))
+        assert_(af.dtype == np.dtype(float))
+
+    def test_lengths(self):
+        expected = np.array(list(self.makegen()))
+        a = np.fromiter(self.makegen(), int)
+        a20 = np.fromiter(self.makegen(), int, 20)
+        assert_(len(a) == len(expected))
+        assert_(len(a20) == 20)
+        assert_raises(ValueError, np.fromiter,
+                          self.makegen(), int, len(expected) + 10)
+
+    def test_values(self):
+        expected = np.array(list(self.makegen()))
+        a = np.fromiter(self.makegen(), int)
+        a20 = np.fromiter(self.makegen(), int, 20)
+        assert_(np.all(a == expected, axis=0))
+        assert_(np.all(a20 == expected[:20], axis=0))
+
+    def load_data(self, n, eindex):
+        # Utility method for the issue 2592 tests.
+        # Raise an exception at the desired index in the iterator.
+        for e in range(n):
+            if e == eindex:
+                raise NIterError('error at index %s' % eindex)
+            yield e
+
+    @pytest.mark.parametrize("dtype", [int, object])
+    @pytest.mark.parametrize(["count", "error_index"], [(10, 5), (10, 9)])
+    def test_2592(self, count, error_index, dtype):
+        # Test iteration exceptions are correctly raised. The data/generator
+        # has `count` elements but errors at `error_index`
+        iterable = self.load_data(count, error_index)
+        with pytest.raises(NIterError):
+            np.fromiter(iterable, dtype=dtype, count=count)
+
+    @pytest.mark.parametrize("dtype", ["S", "S0", "V0", "U0"])
+    def test_empty_not_structured(self, dtype):
+        # Note, "S0" could be allowed at some point, so long "S" (without
+        # any length) is rejected.
+        with pytest.raises(ValueError, match="Must specify length"):
+            np.fromiter([], dtype=dtype)
+
+    @pytest.mark.parametrize(["dtype", "data"],
+            [("d", [1, 2, 3, 4, 5, 6, 7, 8, 9]),
+             ("O", [1, 2, 3, 4, 5, 6, 7, 8, 9]),
+             ("i,O", [(1, 2), (5, 4), (2, 3), (9, 8), (6, 7)]),
+             # subarray dtypes (important because their dimensions end up
+             # in the result arrays dimension:
+             ("2i", [(1, 2), (5, 4), (2, 3), (9, 8), (6, 7)]),
+             (np.dtype(("O", (2, 3))),
+              [((1, 2, 3), (3, 4, 5)), ((3, 2, 1), (5, 4, 3))])])
+    @pytest.mark.parametrize("length_hint", [0, 1])
+    def test_growth_and_complicated_dtypes(self, dtype, data, length_hint):
+        dtype = np.dtype(dtype)
+
+        data = data * 100  # make sure we realloc a bit
+
+        class MyIter:
+            # Class/example from gh-15789
+            def __length_hint__(self):
+                # only required to be an estimate, this is legal
+                return length_hint  # 0 or 1
+
+            def __iter__(self):
+                return iter(data)
+
+        res = np.fromiter(MyIter(), dtype=dtype)
+        expected = np.array(data, dtype=dtype)
+
+        assert_array_equal(res, expected)
+
+    def test_empty_result(self):
+        class MyIter:
+            def __length_hint__(self):
+                return 10
+
+            def __iter__(self):
+                return iter([])  # actual iterator is empty.
+
+        res = np.fromiter(MyIter(), dtype="d")
+        assert res.shape == (0,)
+        assert res.dtype == "d"
+
+    def test_too_few_items(self):
+        msg = "iterator too short: Expected 10 but iterator had only 3 items."
+        with pytest.raises(ValueError, match=msg):
+            np.fromiter([1, 2, 3], count=10, dtype=int)
+
+    def test_failed_itemsetting(self):
+        with pytest.raises(TypeError):
+            np.fromiter([1, None, 3], dtype=int)
+
+        # The following manages to hit somewhat trickier code paths:
+        iterable = ((2, 3, 4) for i in range(5))
+        with pytest.raises(ValueError):
+            np.fromiter(iterable, dtype=np.dtype((int, 2)))
+
+class TestNonzero:
+    def test_nonzero_trivial(self):
+        assert_equal(np.count_nonzero(np.array([])), 0)
+        assert_equal(np.count_nonzero(np.array([], dtype='?')), 0)
+        assert_equal(np.nonzero(np.array([])), ([],))
+
+        assert_equal(np.count_nonzero(np.array([0])), 0)
+        assert_equal(np.count_nonzero(np.array([0], dtype='?')), 0)
+        assert_equal(np.nonzero(np.array([0])), ([],))
+
+        assert_equal(np.count_nonzero(np.array([1])), 1)
+        assert_equal(np.count_nonzero(np.array([1], dtype='?')), 1)
+        assert_equal(np.nonzero(np.array([1])), ([0],))
+
+    def test_nonzero_zerod(self):
+        assert_equal(np.count_nonzero(np.array(0)), 0)
+        assert_equal(np.count_nonzero(np.array(0, dtype='?')), 0)
+        with assert_warns(DeprecationWarning):
+            assert_equal(np.nonzero(np.array(0)), ([],))
+
+        assert_equal(np.count_nonzero(np.array(1)), 1)
+        assert_equal(np.count_nonzero(np.array(1, dtype='?')), 1)
+        with assert_warns(DeprecationWarning):
+            assert_equal(np.nonzero(np.array(1)), ([0],))
+
+    def test_nonzero_onedim(self):
+        x = np.array([1, 0, 2, -1, 0, 0, 8])
+        assert_equal(np.count_nonzero(x), 4)
+        assert_equal(np.count_nonzero(x), 4)
+        assert_equal(np.nonzero(x), ([0, 2, 3, 6],))
+
+        # x = np.array([(1, 2), (0, 0), (1, 1), (-1, 3), (0, 7)],
+        #              dtype=[('a', 'i4'), ('b', 'i2')])
+        x = np.array([(1, 2, -5, -3), (0, 0, 2, 7), (1, 1, 0, 1), (-1, 3, 1, 0), (0, 7, 0, 4)],
+                     dtype=[('a', 'i4'), ('b', 'i2'), ('c', 'i1'), ('d', 'i8')])
+        assert_equal(np.count_nonzero(x['a']), 3)
+        assert_equal(np.count_nonzero(x['b']), 4)
+        assert_equal(np.count_nonzero(x['c']), 3)
+        assert_equal(np.count_nonzero(x['d']), 4)
+        assert_equal(np.nonzero(x['a']), ([0, 2, 3],))
+        assert_equal(np.nonzero(x['b']), ([0, 2, 3, 4],))
+
+    def test_nonzero_twodim(self):
+        x = np.array([[0, 1, 0], [2, 0, 3]])
+        assert_equal(np.count_nonzero(x.astype('i1')), 3)
+        assert_equal(np.count_nonzero(x.astype('i2')), 3)
+        assert_equal(np.count_nonzero(x.astype('i4')), 3)
+        assert_equal(np.count_nonzero(x.astype('i8')), 3)
+        assert_equal(np.nonzero(x), ([0, 1, 1], [1, 0, 2]))
+
+        x = np.eye(3)
+        assert_equal(np.count_nonzero(x.astype('i1')), 3)
+        assert_equal(np.count_nonzero(x.astype('i2')), 3)
+        assert_equal(np.count_nonzero(x.astype('i4')), 3)
+        assert_equal(np.count_nonzero(x.astype('i8')), 3)
+        assert_equal(np.nonzero(x), ([0, 1, 2], [0, 1, 2]))
+
+        x = np.array([[(0, 1), (0, 0), (1, 11)],
+                   [(1, 1), (1, 0), (0, 0)],
+                   [(0, 0), (1, 5), (0, 1)]], dtype=[('a', 'f4'), ('b', 'u1')])
+        assert_equal(np.count_nonzero(x['a']), 4)
+        assert_equal(np.count_nonzero(x['b']), 5)
+        assert_equal(np.nonzero(x['a']), ([0, 1, 1, 2], [2, 0, 1, 1]))
+        assert_equal(np.nonzero(x['b']), ([0, 0, 1, 2, 2], [0, 2, 0, 1, 2]))
+
+        assert_(not x['a'].T.flags.aligned)
+        assert_equal(np.count_nonzero(x['a'].T), 4)
+        assert_equal(np.count_nonzero(x['b'].T), 5)
+        assert_equal(np.nonzero(x['a'].T), ([0, 1, 1, 2], [1, 1, 2, 0]))
+        assert_equal(np.nonzero(x['b'].T), ([0, 0, 1, 2, 2], [0, 1, 2, 0, 2]))
+
+    def test_sparse(self):
+        # test special sparse condition boolean code path
+        for i in range(20):
+            c = np.zeros(200, dtype=bool)
+            c[i::20] = True
+            assert_equal(np.nonzero(c)[0], np.arange(i, 200 + i, 20))
+
+            c = np.zeros(400, dtype=bool)
+            c[10 + i:20 + i] = True
+            c[20 + i*2] = True
+            assert_equal(np.nonzero(c)[0],
+                         np.concatenate((np.arange(10 + i, 20 + i), [20 + i*2])))
+
+    def test_return_type(self):
+        class C(np.ndarray):
+            pass
+
+        for view in (C, np.ndarray):
+            for nd in range(1, 4):
+                shape = tuple(range(2, 2+nd))
+                x = np.arange(np.prod(shape)).reshape(shape).view(view)
+                for nzx in (np.nonzero(x), x.nonzero()):
+                    for nzx_i in nzx:
+                        assert_(type(nzx_i) is np.ndarray)
+                        assert_(nzx_i.flags.writeable)
+
+    def test_count_nonzero_axis(self):
+        # Basic check of functionality
+        m = np.array([[0, 1, 7, 0, 0], [3, 0, 0, 2, 19]])
+
+        expected = np.array([1, 1, 1, 1, 1])
+        assert_equal(np.count_nonzero(m, axis=0), expected)
+
+        expected = np.array([2, 3])
+        assert_equal(np.count_nonzero(m, axis=1), expected)
+
+        assert_raises(ValueError, np.count_nonzero, m, axis=(1, 1))
+        assert_raises(TypeError, np.count_nonzero, m, axis='foo')
+        assert_raises(np.AxisError, np.count_nonzero, m, axis=3)
+        assert_raises(TypeError, np.count_nonzero,
+                      m, axis=np.array([[1], [2]]))
+
+    def test_count_nonzero_axis_all_dtypes(self):
+        # More thorough test that the axis argument is respected
+        # for all dtypes and responds correctly when presented with
+        # either integer or tuple arguments for axis
+        msg = "Mismatch for dtype: %s"
+
+        def assert_equal_w_dt(a, b, err_msg):
+            assert_equal(a.dtype, b.dtype, err_msg=err_msg)
+            assert_equal(a, b, err_msg=err_msg)
+
+        for dt in np.typecodes['All']:
+            err_msg = msg % (np.dtype(dt).name,)
+
+            if dt != 'V':
+                if dt != 'M':
+                    m = np.zeros((3, 3), dtype=dt)
+                    n = np.ones(1, dtype=dt)
+
+                    m[0, 0] = n[0]
+                    m[1, 0] = n[0]
+
+                else:  # np.zeros doesn't work for np.datetime64
+                    m = np.array(['1970-01-01'] * 9)
+                    m = m.reshape((3, 3))
+
+                    m[0, 0] = '1970-01-12'
+                    m[1, 0] = '1970-01-12'
+                    m = m.astype(dt)
+
+                expected = np.array([2, 0, 0], dtype=np.intp)
+                assert_equal_w_dt(np.count_nonzero(m, axis=0),
+                                  expected, err_msg=err_msg)
+
+                expected = np.array([1, 1, 0], dtype=np.intp)
+                assert_equal_w_dt(np.count_nonzero(m, axis=1),
+                                  expected, err_msg=err_msg)
+
+                expected = np.array(2)
+                assert_equal(np.count_nonzero(m, axis=(0, 1)),
+                             expected, err_msg=err_msg)
+                assert_equal(np.count_nonzero(m, axis=None),
+                             expected, err_msg=err_msg)
+                assert_equal(np.count_nonzero(m),
+                             expected, err_msg=err_msg)
+
+            if dt == 'V':
+                # There are no 'nonzero' objects for np.void, so the testing
+                # setup is slightly different for this dtype
+                m = np.array([np.void(1)] * 6).reshape((2, 3))
+
+                expected = np.array([0, 0, 0], dtype=np.intp)
+                assert_equal_w_dt(np.count_nonzero(m, axis=0),
+                                  expected, err_msg=err_msg)
+
+                expected = np.array([0, 0], dtype=np.intp)
+                assert_equal_w_dt(np.count_nonzero(m, axis=1),
+                                  expected, err_msg=err_msg)
+
+                expected = np.array(0)
+                assert_equal(np.count_nonzero(m, axis=(0, 1)),
+                             expected, err_msg=err_msg)
+                assert_equal(np.count_nonzero(m, axis=None),
+                             expected, err_msg=err_msg)
+                assert_equal(np.count_nonzero(m),
+                             expected, err_msg=err_msg)
+
+    def test_count_nonzero_axis_consistent(self):
+        # Check that the axis behaviour for valid axes in
+        # non-special cases is consistent (and therefore
+        # correct) by checking it against an integer array
+        # that is then casted to the generic object dtype
+        from itertools import combinations, permutations
+
+        axis = (0, 1, 2, 3)
+        size = (5, 5, 5, 5)
+        msg = "Mismatch for axis: %s"
+
+        rng = np.random.RandomState(1234)
+        m = rng.randint(-100, 100, size=size)
+        n = m.astype(object)
+
+        for length in range(len(axis)):
+            for combo in combinations(axis, length):
+                for perm in permutations(combo):
+                    assert_equal(
+                        np.count_nonzero(m, axis=perm),
+                        np.count_nonzero(n, axis=perm),
+                        err_msg=msg % (perm,))
+
+    def test_countnonzero_axis_empty(self):
+        a = np.array([[0, 0, 1], [1, 0, 1]])
+        assert_equal(np.count_nonzero(a, axis=()), a.astype(bool))
+
+    def test_countnonzero_keepdims(self):
+        a = np.array([[0, 0, 1, 0],
+                      [0, 3, 5, 0],
+                      [7, 9, 2, 0]])
+        assert_equal(np.count_nonzero(a, axis=0, keepdims=True),
+                     [[1, 2, 3, 0]])
+        assert_equal(np.count_nonzero(a, axis=1, keepdims=True),
+                     [[1], [2], [3]])
+        assert_equal(np.count_nonzero(a, keepdims=True),
+                     [[6]])
+
+    def test_array_method(self):
+        # Tests that the array method
+        # call to nonzero works
+        m = np.array([[1, 0, 0], [4, 0, 6]])
+        tgt = [[0, 1, 1], [0, 0, 2]]
+
+        assert_equal(m.nonzero(), tgt)
+
+    def test_nonzero_invalid_object(self):
+        # gh-9295
+        a = np.array([np.array([1, 2]), 3], dtype=object)
+        assert_raises(ValueError, np.nonzero, a)
+
+        class BoolErrors:
+            def __bool__(self):
+                raise ValueError("Not allowed")
+
+        assert_raises(ValueError, np.nonzero, np.array([BoolErrors()]))
+
+    def test_nonzero_sideeffect_safety(self):
+        # gh-13631
+        class FalseThenTrue:
+            _val = False
+            def __bool__(self):
+                try:
+                    return self._val
+                finally:
+                    self._val = True
+
+        class TrueThenFalse:
+            _val = True
+            def __bool__(self):
+                try:
+                    return self._val
+                finally:
+                    self._val = False
+
+        # result grows on the second pass
+        a = np.array([True, FalseThenTrue()])
+        assert_raises(RuntimeError, np.nonzero, a)
+
+        a = np.array([[True], [FalseThenTrue()]])
+        assert_raises(RuntimeError, np.nonzero, a)
+
+        # result shrinks on the second pass
+        a = np.array([False, TrueThenFalse()])
+        assert_raises(RuntimeError, np.nonzero, a)
+
+        a = np.array([[False], [TrueThenFalse()]])
+        assert_raises(RuntimeError, np.nonzero, a)
+
+    def test_nonzero_sideffects_structured_void(self):
+        # Checks that structured void does not mutate alignment flag of
+        # original array.
+        arr = np.zeros(5, dtype="i1,i8,i8")  # `ones` may short-circuit
+        assert arr.flags.aligned  # structs are considered "aligned"
+        assert not arr["f2"].flags.aligned
+        # make sure that nonzero/count_nonzero do not flip the flag:
+        np.nonzero(arr)
+        assert arr.flags.aligned
+        np.count_nonzero(arr)
+        assert arr.flags.aligned
+
+    def test_nonzero_exception_safe(self):
+        # gh-13930
+
+        class ThrowsAfter:
+            def __init__(self, iters):
+                self.iters_left = iters
+
+            def __bool__(self):
+                if self.iters_left == 0:
+                    raise ValueError("called `iters` times")
+
+                self.iters_left -= 1
+                return True
+
+        """
+        Test that a ValueError is raised instead of a SystemError
+
+        If the __bool__ function is called after the error state is set,
+        Python (cpython) will raise a SystemError.
+        """
+
+        # assert that an exception in first pass is handled correctly
+        a = np.array([ThrowsAfter(5)]*10)
+        assert_raises(ValueError, np.nonzero, a)
+
+        # raise exception in second pass for 1-dimensional loop
+        a = np.array([ThrowsAfter(15)]*10)
+        assert_raises(ValueError, np.nonzero, a)
+
+        # raise exception in second pass for n-dimensional loop
+        a = np.array([[ThrowsAfter(15)]]*10)
+        assert_raises(ValueError, np.nonzero, a)
+
+    @pytest.mark.skipif(IS_WASM, reason="wasm doesn't have threads")
+    def test_structured_threadsafety(self):
+        # Nonzero (and some other functions) should be threadsafe for
+        # structured datatypes, see gh-15387. This test can behave randomly.
+        from concurrent.futures import ThreadPoolExecutor
+
+        # Create a deeply nested dtype to make a failure more likely:
+        dt = np.dtype([("", "f8")])
+        dt = np.dtype([("", dt)])
+        dt = np.dtype([("", dt)] * 2)
+        # The array should be large enough to likely run into threading issues
+        arr = np.random.uniform(size=(5000, 4)).view(dt)[:, 0]
+        def func(arr):
+            arr.nonzero()
+
+        tpe = ThreadPoolExecutor(max_workers=8)
+        futures = [tpe.submit(func, arr) for _ in range(10)]
+        for f in futures:
+            f.result()
+
+        assert arr.dtype is dt
+
+
+class TestIndex:
+    def test_boolean(self):
+        a = rand(3, 5, 8)
+        V = rand(5, 8)
+        g1 = randint(0, 5, size=15)
+        g2 = randint(0, 8, size=15)
+        V[g1, g2] = -V[g1, g2]
+        assert_((np.array([a[0][V > 0], a[1][V > 0], a[2][V > 0]]) == a[:, V > 0]).all())
+
+    def test_boolean_edgecase(self):
+        a = np.array([], dtype='int32')
+        b = np.array([], dtype='bool')
+        c = a[b]
+        assert_equal(c, [])
+        assert_equal(c.dtype, np.dtype('int32'))
+
+
+class TestBinaryRepr:
+    def test_zero(self):
+        assert_equal(np.binary_repr(0), '0')
+
+    def test_positive(self):
+        assert_equal(np.binary_repr(10), '1010')
+        assert_equal(np.binary_repr(12522),
+                     '11000011101010')
+        assert_equal(np.binary_repr(10736848),
+                     '101000111101010011010000')
+
+    def test_negative(self):
+        assert_equal(np.binary_repr(-1), '-1')
+        assert_equal(np.binary_repr(-10), '-1010')
+        assert_equal(np.binary_repr(-12522),
+                     '-11000011101010')
+        assert_equal(np.binary_repr(-10736848),
+                     '-101000111101010011010000')
+
+    def test_sufficient_width(self):
+        assert_equal(np.binary_repr(0, width=5), '00000')
+        assert_equal(np.binary_repr(10, width=7), '0001010')
+        assert_equal(np.binary_repr(-5, width=7), '1111011')
+
+    def test_neg_width_boundaries(self):
+        # see gh-8670
+
+        # Ensure that the example in the issue does not
+        # break before proceeding to a more thorough test.
+        assert_equal(np.binary_repr(-128, width=8), '10000000')
+
+        for width in range(1, 11):
+            num = -2**(width - 1)
+            exp = '1' + (width - 1) * '0'
+            assert_equal(np.binary_repr(num, width=width), exp)
+
+    def test_large_neg_int64(self):
+        # See gh-14289.
+        assert_equal(np.binary_repr(np.int64(-2**62), width=64),
+                     '11' + '0'*62)
+
+
+class TestBaseRepr:
+    def test_base3(self):
+        assert_equal(np.base_repr(3**5, 3), '100000')
+
+    def test_positive(self):
+        assert_equal(np.base_repr(12, 10), '12')
+        assert_equal(np.base_repr(12, 10, 4), '000012')
+        assert_equal(np.base_repr(12, 4), '30')
+        assert_equal(np.base_repr(3731624803700888, 36), '10QR0ROFCEW')
+
+    def test_negative(self):
+        assert_equal(np.base_repr(-12, 10), '-12')
+        assert_equal(np.base_repr(-12, 10, 4), '-000012')
+        assert_equal(np.base_repr(-12, 4), '-30')
+
+    def test_base_range(self):
+        with assert_raises(ValueError):
+            np.base_repr(1, 1)
+        with assert_raises(ValueError):
+            np.base_repr(1, 37)
+
+
+class TestArrayComparisons:
+    def test_array_equal(self):
+        res = np.array_equal(np.array([1, 2]), np.array([1, 2]))
+        assert_(res)
+        assert_(type(res) is bool)
+        res = np.array_equal(np.array([1, 2]), np.array([1, 2, 3]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equal(np.array([1, 2]), np.array([3, 4]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equal(np.array([1, 2]), np.array([1, 3]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equal(np.array(['a'], dtype='S1'), np.array(['a'], dtype='S1'))
+        assert_(res)
+        assert_(type(res) is bool)
+        res = np.array_equal(np.array([('a', 1)], dtype='S1,u4'),
+                             np.array([('a', 1)], dtype='S1,u4'))
+        assert_(res)
+        assert_(type(res) is bool)
+
+    def test_array_equal_equal_nan(self):
+        # Test array_equal with equal_nan kwarg
+        a1 = np.array([1, 2, np.nan])
+        a2 = np.array([1, np.nan, 2])
+        a3 = np.array([1, 2, np.inf])
+
+        # equal_nan=False by default
+        assert_(not np.array_equal(a1, a1))
+        assert_(np.array_equal(a1, a1, equal_nan=True))
+        assert_(not np.array_equal(a1, a2, equal_nan=True))
+        # nan's not conflated with inf's
+        assert_(not np.array_equal(a1, a3, equal_nan=True))
+        # 0-D arrays
+        a = np.array(np.nan)
+        assert_(not np.array_equal(a, a))
+        assert_(np.array_equal(a, a, equal_nan=True))
+        # Non-float dtype - equal_nan should have no effect
+        a = np.array([1, 2, 3], dtype=int)
+        assert_(np.array_equal(a, a))
+        assert_(np.array_equal(a, a, equal_nan=True))
+        # Multi-dimensional array
+        a = np.array([[0, 1], [np.nan, 1]])
+        assert_(not np.array_equal(a, a))
+        assert_(np.array_equal(a, a, equal_nan=True))
+        # Complex values
+        a, b = [np.array([1 + 1j])]*2
+        a.real, b.imag = np.nan, np.nan
+        assert_(not np.array_equal(a, b, equal_nan=False))
+        assert_(np.array_equal(a, b, equal_nan=True))
+
+    def test_none_compares_elementwise(self):
+        a = np.array([None, 1, None], dtype=object)
+        assert_equal(a == None, [True, False, True])
+        assert_equal(a != None, [False, True, False])
+
+        a = np.ones(3)
+        assert_equal(a == None, [False, False, False])
+        assert_equal(a != None, [True, True, True])
+
+    def test_array_equiv(self):
+        res = np.array_equiv(np.array([1, 2]), np.array([1, 2]))
+        assert_(res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([1, 2, 3]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([3, 4]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([1, 3]))
+        assert_(not res)
+        assert_(type(res) is bool)
+
+        res = np.array_equiv(np.array([1, 1]), np.array([1]))
+        assert_(res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 1]), np.array([[1], [1]]))
+        assert_(res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([2]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([[1], [2]]))
+        assert_(not res)
+        assert_(type(res) is bool)
+        res = np.array_equiv(np.array([1, 2]), np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]))
+        assert_(not res)
+        assert_(type(res) is bool)
+
+    @pytest.mark.parametrize("dtype", ["V0", "V3", "V10"])
+    def test_compare_unstructured_voids(self, dtype):
+        zeros = np.zeros(3, dtype=dtype)
+
+        assert_array_equal(zeros, zeros)
+        assert not (zeros != zeros).any()
+
+        if dtype == "V0":
+            # Can't test != of actually different data
+            return
+
+        nonzeros = np.array([b"1", b"2", b"3"], dtype=dtype)
+
+        assert not (zeros == nonzeros).any()
+        assert (zeros != nonzeros).all()
+
+
+def assert_array_strict_equal(x, y):
+    assert_array_equal(x, y)
+    # Check flags, 32 bit arches typically don't provide 16 byte alignment
+    if ((x.dtype.alignment <= 8 or
+            np.intp().dtype.itemsize != 4) and
+            sys.platform != 'win32'):
+        assert_(x.flags == y.flags)
+    else:
+        assert_(x.flags.owndata == y.flags.owndata)
+        assert_(x.flags.writeable == y.flags.writeable)
+        assert_(x.flags.c_contiguous == y.flags.c_contiguous)
+        assert_(x.flags.f_contiguous == y.flags.f_contiguous)
+        assert_(x.flags.writebackifcopy == y.flags.writebackifcopy)
+    # check endianness
+    assert_(x.dtype.isnative == y.dtype.isnative)
+
+
+class TestClip:
+    def setup_method(self):
+        self.nr = 5
+        self.nc = 3
+
+    def fastclip(self, a, m, M, out=None, **kwargs):
+        return a.clip(m, M, out=out, **kwargs)
+
+    def clip(self, a, m, M, out=None):
+        # use a.choose to verify fastclip result
+        selector = np.less(a, m) + 2*np.greater(a, M)
+        return selector.choose((a, m, M), out=out)
+
+    # Handy functions
+    def _generate_data(self, n, m):
+        return randn(n, m)
+
+    def _generate_data_complex(self, n, m):
+        return randn(n, m) + 1.j * rand(n, m)
+
+    def _generate_flt_data(self, n, m):
+        return (randn(n, m)).astype(np.float32)
+
+    def _neg_byteorder(self, a):
+        a = np.asarray(a)
+        if sys.byteorder == 'little':
+            a = a.astype(a.dtype.newbyteorder('>'))
+        else:
+            a = a.astype(a.dtype.newbyteorder('<'))
+        return a
+
+    def _generate_non_native_data(self, n, m):
+        data = randn(n, m)
+        data = self._neg_byteorder(data)
+        assert_(not data.dtype.isnative)
+        return data
+
+    def _generate_int_data(self, n, m):
+        return (10 * rand(n, m)).astype(np.int64)
+
+    def _generate_int32_data(self, n, m):
+        return (10 * rand(n, m)).astype(np.int32)
+
+    # Now the real test cases
+
+    @pytest.mark.parametrize("dtype", '?bhilqpBHILQPefdgFDGO')
+    def test_ones_pathological(self, dtype):
+        # for preservation of behavior described in
+        # gh-12519; amin > amax behavior may still change
+        # in the future
+        arr = np.ones(10, dtype=dtype)
+        expected = np.zeros(10, dtype=dtype)
+        actual = np.clip(arr, 1, 0)
+        if dtype == 'O':
+            assert actual.tolist() == expected.tolist()
+        else:
+            assert_equal(actual, expected)
+
+    def test_simple_double(self):
+        # Test native double input with scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = 0.1
+        M = 0.6
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_int(self):
+        # Test native int input with scalar min/max.
+        a = self._generate_int_data(self.nr, self.nc)
+        a = a.astype(int)
+        m = -2
+        M = 4
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_array_double(self):
+        # Test native double input with array min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = np.zeros(a.shape)
+        M = m + 0.5
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_nonnative(self):
+        # Test non native double input with scalar min/max.
+        # Test native double input with non native double scalar min/max.
+        a = self._generate_non_native_data(self.nr, self.nc)
+        m = -0.5
+        M = 0.6
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_equal(ac, act)
+
+        # Test native double input with non native double scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5
+        M = self._neg_byteorder(0.6)
+        assert_(not M.dtype.isnative)
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_equal(ac, act)
+
+    def test_simple_complex(self):
+        # Test native complex input with native double scalar min/max.
+        # Test native input with complex double scalar min/max.
+        a = 3 * self._generate_data_complex(self.nr, self.nc)
+        m = -0.5
+        M = 1.
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+        # Test native input with complex double scalar min/max.
+        a = 3 * self._generate_data(self.nr, self.nc)
+        m = -0.5 + 1.j
+        M = 1. + 2.j
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_complex(self):
+        # Address Issue gh-5354 for clipping complex arrays
+        # Test native complex input without explicit min/max
+        # ie, either min=None or max=None
+        a = np.ones(10, dtype=complex)
+        m = a.min()
+        M = a.max()
+        am = self.fastclip(a, m, None)
+        aM = self.fastclip(a, None, M)
+        assert_array_strict_equal(am, a)
+        assert_array_strict_equal(aM, a)
+
+    def test_clip_non_contig(self):
+        # Test clip for non contiguous native input and native scalar min/max.
+        a = self._generate_data(self.nr * 2, self.nc * 3)
+        a = a[::2, ::3]
+        assert_(not a.flags['F_CONTIGUOUS'])
+        assert_(not a.flags['C_CONTIGUOUS'])
+        ac = self.fastclip(a, -1.6, 1.7)
+        act = self.clip(a, -1.6, 1.7)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_out(self):
+        # Test native double input with scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5
+        M = 0.6
+        ac = np.zeros(a.shape)
+        act = np.zeros(a.shape)
+        self.fastclip(a, m, M, ac)
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    @pytest.mark.parametrize("casting", [None, "unsafe"])
+    def test_simple_int32_inout(self, casting):
+        # Test native int32 input with double min/max and int32 out.
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.float64(0)
+        M = np.float64(2)
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        if casting is None:
+            with pytest.raises(TypeError):
+                self.fastclip(a, m, M, ac, casting=casting)
+        else:
+            # explicitly passing "unsafe" will silence warning
+            self.fastclip(a, m, M, ac, casting=casting)
+            self.clip(a, m, M, act)
+            assert_array_strict_equal(ac, act)
+
+    def test_simple_int64_out(self):
+        # Test native int32 input with int32 scalar min/max and int64 out.
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.int32(-1)
+        M = np.int32(1)
+        ac = np.zeros(a.shape, dtype=np.int64)
+        act = ac.copy()
+        self.fastclip(a, m, M, ac)
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_int64_inout(self):
+        # Test native int32 input with double array min/max and int32 out.
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.zeros(a.shape, np.float64)
+        M = np.float64(1)
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        self.fastclip(a, m, M, out=ac, casting="unsafe")
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_int32_out(self):
+        # Test native double input with scalar min/max and int out.
+        a = self._generate_data(self.nr, self.nc)
+        m = -1.0
+        M = 2.0
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        self.fastclip(a, m, M, out=ac, casting="unsafe")
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_simple_inplace_01(self):
+        # Test native double input with array min/max in-place.
+        a = self._generate_data(self.nr, self.nc)
+        ac = a.copy()
+        m = np.zeros(a.shape)
+        M = 1.0
+        self.fastclip(a, m, M, a)
+        self.clip(a, m, M, ac)
+        assert_array_strict_equal(a, ac)
+
+    def test_simple_inplace_02(self):
+        # Test native double input with scalar min/max in-place.
+        a = self._generate_data(self.nr, self.nc)
+        ac = a.copy()
+        m = -0.5
+        M = 0.6
+        self.fastclip(a, m, M, a)
+        self.clip(ac, m, M, ac)
+        assert_array_strict_equal(a, ac)
+
+    def test_noncontig_inplace(self):
+        # Test non contiguous double input with double scalar min/max in-place.
+        a = self._generate_data(self.nr * 2, self.nc * 3)
+        a = a[::2, ::3]
+        assert_(not a.flags['F_CONTIGUOUS'])
+        assert_(not a.flags['C_CONTIGUOUS'])
+        ac = a.copy()
+        m = -0.5
+        M = 0.6
+        self.fastclip(a, m, M, a)
+        self.clip(ac, m, M, ac)
+        assert_array_equal(a, ac)
+
+    def test_type_cast_01(self):
+        # Test native double input with scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5
+        M = 0.6
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_02(self):
+        # Test native int32 input with int32 scalar min/max.
+        a = self._generate_int_data(self.nr, self.nc)
+        a = a.astype(np.int32)
+        m = -2
+        M = 4
+        ac = self.fastclip(a, m, M)
+        act = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_03(self):
+        # Test native int32 input with float64 scalar min/max.
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = -2
+        M = 4
+        ac = self.fastclip(a, np.float64(m), np.float64(M))
+        act = self.clip(a, np.float64(m), np.float64(M))
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_04(self):
+        # Test native int32 input with float32 scalar min/max.
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.float32(-2)
+        M = np.float32(4)
+        act = self.fastclip(a, m, M)
+        ac = self.clip(a, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_05(self):
+        # Test native int32 with double arrays min/max.
+        a = self._generate_int_data(self.nr, self.nc)
+        m = -0.5
+        M = 1.
+        ac = self.fastclip(a, m * np.zeros(a.shape), M)
+        act = self.clip(a, m * np.zeros(a.shape), M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_06(self):
+        # Test native with NON native scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = 0.5
+        m_s = self._neg_byteorder(m)
+        M = 1.
+        act = self.clip(a, m_s, M)
+        ac = self.fastclip(a, m_s, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_07(self):
+        # Test NON native with native array min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5 * np.ones(a.shape)
+        M = 1.
+        a_s = self._neg_byteorder(a)
+        assert_(not a_s.dtype.isnative)
+        act = a_s.clip(m, M)
+        ac = self.fastclip(a_s, m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_08(self):
+        # Test NON native with native scalar min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5
+        M = 1.
+        a_s = self._neg_byteorder(a)
+        assert_(not a_s.dtype.isnative)
+        ac = self.fastclip(a_s, m, M)
+        act = a_s.clip(m, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_09(self):
+        # Test native with NON native array min/max.
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5 * np.ones(a.shape)
+        M = 1.
+        m_s = self._neg_byteorder(m)
+        assert_(not m_s.dtype.isnative)
+        ac = self.fastclip(a, m_s, M)
+        act = self.clip(a, m_s, M)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_10(self):
+        # Test native int32 with float min/max and float out for output argument.
+        a = self._generate_int_data(self.nr, self.nc)
+        b = np.zeros(a.shape, dtype=np.float32)
+        m = np.float32(-0.5)
+        M = np.float32(1)
+        act = self.clip(a, m, M, out=b)
+        ac = self.fastclip(a, m, M, out=b)
+        assert_array_strict_equal(ac, act)
+
+    def test_type_cast_11(self):
+        # Test non native with native scalar, min/max, out non native
+        a = self._generate_non_native_data(self.nr, self.nc)
+        b = a.copy()
+        b = b.astype(b.dtype.newbyteorder('>'))
+        bt = b.copy()
+        m = -0.5
+        M = 1.
+        self.fastclip(a, m, M, out=b)
+        self.clip(a, m, M, out=bt)
+        assert_array_strict_equal(b, bt)
+
+    def test_type_cast_12(self):
+        # Test native int32 input and min/max and float out
+        a = self._generate_int_data(self.nr, self.nc)
+        b = np.zeros(a.shape, dtype=np.float32)
+        m = np.int32(0)
+        M = np.int32(1)
+        act = self.clip(a, m, M, out=b)
+        ac = self.fastclip(a, m, M, out=b)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_simple(self):
+        # Test native double input with scalar min/max
+        a = self._generate_data(self.nr, self.nc)
+        m = -0.5
+        M = 0.6
+        ac = np.zeros(a.shape)
+        act = np.zeros(a.shape)
+        self.fastclip(a, m, M, ac)
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_simple2(self):
+        # Test native int32 input with double min/max and int32 out
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.float64(0)
+        M = np.float64(2)
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        self.fastclip(a, m, M, out=ac, casting="unsafe")
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_simple_int32(self):
+        # Test native int32 input with int32 scalar min/max and int64 out
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.int32(-1)
+        M = np.int32(1)
+        ac = np.zeros(a.shape, dtype=np.int64)
+        act = ac.copy()
+        self.fastclip(a, m, M, ac)
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_array_int32(self):
+        # Test native int32 input with double array min/max and int32 out
+        a = self._generate_int32_data(self.nr, self.nc)
+        m = np.zeros(a.shape, np.float64)
+        M = np.float64(1)
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        self.fastclip(a, m, M, out=ac, casting="unsafe")
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_array_outint32(self):
+        # Test native double input with scalar min/max and int out
+        a = self._generate_data(self.nr, self.nc)
+        m = -1.0
+        M = 2.0
+        ac = np.zeros(a.shape, dtype=np.int32)
+        act = ac.copy()
+        self.fastclip(a, m, M, out=ac, casting="unsafe")
+        self.clip(a, m, M, act)
+        assert_array_strict_equal(ac, act)
+
+    def test_clip_with_out_transposed(self):
+        # Test that the out argument works when transposed
+        a = np.arange(16).reshape(4, 4)
+        out = np.empty_like(a).T
+        a.clip(4, 10, out=out)
+        expected = self.clip(a, 4, 10)
+        assert_array_equal(out, expected)
+
+    def test_clip_with_out_memory_overlap(self):
+        # Test that the out argument works when it has memory overlap
+        a = np.arange(16).reshape(4, 4)
+        ac = a.copy()
+        a[:-1].clip(4, 10, out=a[1:])
+        expected = self.clip(ac[:-1], 4, 10)
+        assert_array_equal(a[1:], expected)
+
+    def test_clip_inplace_array(self):
+        # Test native double input with array min/max
+        a = self._generate_data(self.nr, self.nc)
+        ac = a.copy()
+        m = np.zeros(a.shape)
+        M = 1.0
+        self.fastclip(a, m, M, a)
+        self.clip(a, m, M, ac)
+        assert_array_strict_equal(a, ac)
+
+    def test_clip_inplace_simple(self):
+        # Test native double input with scalar min/max
+        a = self._generate_data(self.nr, self.nc)
+        ac = a.copy()
+        m = -0.5
+        M = 0.6
+        self.fastclip(a, m, M, a)
+        self.clip(a, m, M, ac)
+        assert_array_strict_equal(a, ac)
+
+    def test_clip_func_takes_out(self):
+        # Ensure that the clip() function takes an out=argument.
+        a = self._generate_data(self.nr, self.nc)
+        ac = a.copy()
+        m = -0.5
+        M = 0.6
+        a2 = np.clip(a, m, M, out=a)
+        self.clip(a, m, M, ac)
+        assert_array_strict_equal(a2, ac)
+        assert_(a2 is a)
+
+    def test_clip_nan(self):
+        d = np.arange(7.)
+        assert_equal(d.clip(min=np.nan), np.nan)
+        assert_equal(d.clip(max=np.nan), np.nan)
+        assert_equal(d.clip(min=np.nan, max=np.nan), np.nan)
+        assert_equal(d.clip(min=-2, max=np.nan), np.nan)
+        assert_equal(d.clip(min=np.nan, max=10), np.nan)
+
+    def test_object_clip(self):
+        a = np.arange(10, dtype=object)
+        actual = np.clip(a, 1, 5)
+        expected = np.array([1, 1, 2, 3, 4, 5, 5, 5, 5, 5])
+        assert actual.tolist() == expected.tolist()
+
+    def test_clip_all_none(self):
+        a = np.arange(10, dtype=object)
+        with assert_raises_regex(ValueError, 'max or min'):
+            np.clip(a, None, None)
+
+    def test_clip_invalid_casting(self):
+        a = np.arange(10, dtype=object)
+        with assert_raises_regex(ValueError,
+                                 'casting must be one of'):
+            self.fastclip(a, 1, 8, casting="garbage")
+
+    @pytest.mark.parametrize("amin, amax", [
+        # two scalars
+        (1, 0),
+        # mix scalar and array
+        (1, np.zeros(10)),
+        # two arrays
+        (np.ones(10), np.zeros(10)),
+        ])
+    def test_clip_value_min_max_flip(self, amin, amax):
+        a = np.arange(10, dtype=np.int64)
+        # requirement from ufunc_docstrings.py
+        expected = np.minimum(np.maximum(a, amin), amax)
+        actual = np.clip(a, amin, amax)
+        assert_equal(actual, expected)
+
+    @pytest.mark.parametrize("arr, amin, amax, exp", [
+        # for a bug in npy_ObjectClip, based on a
+        # case produced by hypothesis
+        (np.zeros(10, dtype=np.int64),
+         0,
+         -2**64+1,
+         np.full(10, -2**64+1, dtype=object)),
+        # for bugs in NPY_TIMEDELTA_MAX, based on a case
+        # produced by hypothesis
+        (np.zeros(10, dtype='m8') - 1,
+         0,
+         0,
+         np.zeros(10, dtype='m8')),
+    ])
+    def test_clip_problem_cases(self, arr, amin, amax, exp):
+        actual = np.clip(arr, amin, amax)
+        assert_equal(actual, exp)
+
+    @pytest.mark.parametrize("arr, amin, amax", [
+        # problematic scalar nan case from hypothesis
+        (np.zeros(10, dtype=np.int64),
+         np.array(np.nan),
+         np.zeros(10, dtype=np.int32)),
+    ])
+    def test_clip_scalar_nan_propagation(self, arr, amin, amax):
+        # enforcement of scalar nan propagation for comparisons
+        # called through clip()
+        expected = np.minimum(np.maximum(arr, amin), amax)
+        actual = np.clip(arr, amin, amax)
+        assert_equal(actual, expected)
+
+    @pytest.mark.xfail(reason="propagation doesn't match spec")
+    @pytest.mark.parametrize("arr, amin, amax", [
+        (np.array([1] * 10, dtype='m8'),
+         np.timedelta64('NaT'),
+         np.zeros(10, dtype=np.int32)),
+    ])
+    @pytest.mark.filterwarnings("ignore::DeprecationWarning")
+    def test_NaT_propagation(self, arr, amin, amax):
+        # NOTE: the expected function spec doesn't
+        # propagate NaT, but clip() now does
+        expected = np.minimum(np.maximum(arr, amin), amax)
+        actual = np.clip(arr, amin, amax)
+        assert_equal(actual, expected)
+
+    @given(
+        data=st.data(),
+        arr=hynp.arrays(
+            dtype=hynp.integer_dtypes() | hynp.floating_dtypes(),
+            shape=hynp.array_shapes()
+        )
+    )
+    def test_clip_property(self, data, arr):
+        """A property-based test using Hypothesis.
+
+        This aims for maximum generality: it could in principle generate *any*
+        valid inputs to np.clip, and in practice generates much more varied
+        inputs than human testers come up with.
+
+        Because many of the inputs have tricky dependencies - compatible dtypes
+        and mutually-broadcastable shapes - we use `st.data()` strategy draw
+        values *inside* the test function, from strategies we construct based
+        on previous values.  An alternative would be to define a custom strategy
+        with `@st.composite`, but until we have duplicated code inline is fine.
+
+        That accounts for most of the function; the actual test is just three
+        lines to calculate and compare actual vs expected results!
+        """
+        numeric_dtypes = hynp.integer_dtypes() | hynp.floating_dtypes()
+        # Generate shapes for the bounds which can be broadcast with each other
+        # and with the base shape.  Below, we might decide to use scalar bounds,
+        # but it's clearer to generate these shapes unconditionally in advance.
+        in_shapes, result_shape = data.draw(
+            hynp.mutually_broadcastable_shapes(
+                num_shapes=2, base_shape=arr.shape
+            )
+        )
+        # Scalar `nan` is deprecated due to the differing behaviour it shows.
+        s = numeric_dtypes.flatmap(
+            lambda x: hynp.from_dtype(x, allow_nan=False))
+        amin = data.draw(s | hynp.arrays(dtype=numeric_dtypes,
+            shape=in_shapes[0], elements={"allow_nan": False}))
+        amax = data.draw(s | hynp.arrays(dtype=numeric_dtypes,
+            shape=in_shapes[1], elements={"allow_nan": False}))
+
+        # Then calculate our result and expected result and check that they're
+        # equal!  See gh-12519 and gh-19457 for discussion deciding on this
+        # property and the result_type argument.
+        result = np.clip(arr, amin, amax)
+        t = np.result_type(arr, amin, amax)
+        expected = np.minimum(amax, np.maximum(arr, amin, dtype=t), dtype=t)
+        assert result.dtype == t
+        assert_array_equal(result, expected)
+
+
+class TestAllclose:
+    rtol = 1e-5
+    atol = 1e-8
+
+    def setup_method(self):
+        self.olderr = np.seterr(invalid='ignore')
+
+    def teardown_method(self):
+        np.seterr(**self.olderr)
+
+    def tst_allclose(self, x, y):
+        assert_(np.allclose(x, y), "%s and %s not close" % (x, y))
+
+    def tst_not_allclose(self, x, y):
+        assert_(not np.allclose(x, y), "%s and %s shouldn't be close" % (x, y))
+
+    def test_ip_allclose(self):
+        # Parametric test factory.
+        arr = np.array([100, 1000])
+        aran = np.arange(125).reshape((5, 5, 5))
+
+        atol = self.atol
+        rtol = self.rtol
+
+        data = [([1, 0], [1, 0]),
+                ([atol], [0]),
+                ([1], [1+rtol+atol]),
+                (arr, arr + arr*rtol),
+                (arr, arr + arr*rtol + atol*2),
+                (aran, aran + aran*rtol),
+                (np.inf, np.inf),
+                (np.inf, [np.inf])]
+
+        for (x, y) in data:
+            self.tst_allclose(x, y)
+
+    def test_ip_not_allclose(self):
+        # Parametric test factory.
+        aran = np.arange(125).reshape((5, 5, 5))
+
+        atol = self.atol
+        rtol = self.rtol
+
+        data = [([np.inf, 0], [1, np.inf]),
+                ([np.inf, 0], [1, 0]),
+                ([np.inf, np.inf], [1, np.inf]),
+                ([np.inf, np.inf], [1, 0]),
+                ([-np.inf, 0], [np.inf, 0]),
+                ([np.nan, 0], [np.nan, 0]),
+                ([atol*2], [0]),
+                ([1], [1+rtol+atol*2]),
+                (aran, aran + aran*atol + atol*2),
+                (np.array([np.inf, 1]), np.array([0, np.inf]))]
+
+        for (x, y) in data:
+            self.tst_not_allclose(x, y)
+
+    def test_no_parameter_modification(self):
+        x = np.array([np.inf, 1])
+        y = np.array([0, np.inf])
+        np.allclose(x, y)
+        assert_array_equal(x, np.array([np.inf, 1]))
+        assert_array_equal(y, np.array([0, np.inf]))
+
+    def test_min_int(self):
+        # Could make problems because of abs(min_int) == min_int
+        min_int = np.iinfo(np.int_).min
+        a = np.array([min_int], dtype=np.int_)
+        assert_(np.allclose(a, a))
+
+    def test_equalnan(self):
+        x = np.array([1.0, np.nan])
+        assert_(np.allclose(x, x, equal_nan=True))
+
+    def test_return_class_is_ndarray(self):
+        # Issue gh-6475
+        # Check that allclose does not preserve subtypes
+        class Foo(np.ndarray):
+            def __new__(cls, *args, **kwargs):
+                return np.array(*args, **kwargs).view(cls)
+
+        a = Foo([1])
+        assert_(type(np.allclose(a, a)) is bool)
+
+
+class TestIsclose:
+    rtol = 1e-5
+    atol = 1e-8
+
+    def _setup(self):
+        atol = self.atol
+        rtol = self.rtol
+        arr = np.array([100, 1000])
+        aran = np.arange(125).reshape((5, 5, 5))
+
+        self.all_close_tests = [
+                ([1, 0], [1, 0]),
+                ([atol], [0]),
+                ([1], [1 + rtol + atol]),
+                (arr, arr + arr*rtol),
+                (arr, arr + arr*rtol + atol),
+                (aran, aran + aran*rtol),
+                (np.inf, np.inf),
+                (np.inf, [np.inf]),
+                ([np.inf, -np.inf], [np.inf, -np.inf]),
+                ]
+        self.none_close_tests = [
+                ([np.inf, 0], [1, np.inf]),
+                ([np.inf, -np.inf], [1, 0]),
+                ([np.inf, np.inf], [1, -np.inf]),
+                ([np.inf, np.inf], [1, 0]),
+                ([np.nan, 0], [np.nan, -np.inf]),
+                ([atol*2], [0]),
+                ([1], [1 + rtol + atol*2]),
+                (aran, aran + rtol*1.1*aran + atol*1.1),
+                (np.array([np.inf, 1]), np.array([0, np.inf])),
+                ]
+        self.some_close_tests = [
+                ([np.inf, 0], [np.inf, atol*2]),
+                ([atol, 1, 1e6*(1 + 2*rtol) + atol], [0, np.nan, 1e6]),
+                (np.arange(3), [0, 1, 2.1]),
+                (np.nan, [np.nan, np.nan, np.nan]),
+                ([0], [atol, np.inf, -np.inf, np.nan]),
+                (0, [atol, np.inf, -np.inf, np.nan]),
+                ]
+        self.some_close_results = [
+                [True, False],
+                [True, False, False],
+                [True, True, False],
+                [False, False, False],
+                [True, False, False, False],
+                [True, False, False, False],
+                ]
+
+    def test_ip_isclose(self):
+        self._setup()
+        tests = self.some_close_tests
+        results = self.some_close_results
+        for (x, y), result in zip(tests, results):
+            assert_array_equal(np.isclose(x, y), result)
+
+    def tst_all_isclose(self, x, y):
+        assert_(np.all(np.isclose(x, y)), "%s and %s not close" % (x, y))
+
+    def tst_none_isclose(self, x, y):
+        msg = "%s and %s shouldn't be close"
+        assert_(not np.any(np.isclose(x, y)), msg % (x, y))
+
+    def tst_isclose_allclose(self, x, y):
+        msg = "isclose.all() and allclose aren't same for %s and %s"
+        msg2 = "isclose and allclose aren't same for %s and %s"
+        if np.isscalar(x) and np.isscalar(y):
+            assert_(np.isclose(x, y) == np.allclose(x, y), msg=msg2 % (x, y))
+        else:
+            assert_array_equal(np.isclose(x, y).all(), np.allclose(x, y), msg % (x, y))
+
+    def test_ip_all_isclose(self):
+        self._setup()
+        for (x, y) in self.all_close_tests:
+            self.tst_all_isclose(x, y)
+
+    def test_ip_none_isclose(self):
+        self._setup()
+        for (x, y) in self.none_close_tests:
+            self.tst_none_isclose(x, y)
+
+    def test_ip_isclose_allclose(self):
+        self._setup()
+        tests = (self.all_close_tests + self.none_close_tests +
+                 self.some_close_tests)
+        for (x, y) in tests:
+            self.tst_isclose_allclose(x, y)
+
+    def test_equal_nan(self):
+        assert_array_equal(np.isclose(np.nan, np.nan, equal_nan=True), [True])
+        arr = np.array([1.0, np.nan])
+        assert_array_equal(np.isclose(arr, arr, equal_nan=True), [True, True])
+
+    def test_masked_arrays(self):
+        # Make sure to test the output type when arguments are interchanged.
+
+        x = np.ma.masked_where([True, True, False], np.arange(3))
+        assert_(type(x) is type(np.isclose(2, x)))
+        assert_(type(x) is type(np.isclose(x, 2)))
+
+        x = np.ma.masked_where([True, True, False], [np.nan, np.inf, np.nan])
+        assert_(type(x) is type(np.isclose(np.inf, x)))
+        assert_(type(x) is type(np.isclose(x, np.inf)))
+
+        x = np.ma.masked_where([True, True, False], [np.nan, np.nan, np.nan])
+        y = np.isclose(np.nan, x, equal_nan=True)
+        assert_(type(x) is type(y))
+        # Ensure that the mask isn't modified...
+        assert_array_equal([True, True, False], y.mask)
+        y = np.isclose(x, np.nan, equal_nan=True)
+        assert_(type(x) is type(y))
+        # Ensure that the mask isn't modified...
+        assert_array_equal([True, True, False], y.mask)
+
+        x = np.ma.masked_where([True, True, False], [np.nan, np.nan, np.nan])
+        y = np.isclose(x, x, equal_nan=True)
+        assert_(type(x) is type(y))
+        # Ensure that the mask isn't modified...
+        assert_array_equal([True, True, False], y.mask)
+
+    def test_scalar_return(self):
+        assert_(np.isscalar(np.isclose(1, 1)))
+
+    def test_no_parameter_modification(self):
+        x = np.array([np.inf, 1])
+        y = np.array([0, np.inf])
+        np.isclose(x, y)
+        assert_array_equal(x, np.array([np.inf, 1]))
+        assert_array_equal(y, np.array([0, np.inf]))
+
+    def test_non_finite_scalar(self):
+        # GH7014, when two scalars are compared the output should also be a
+        # scalar
+        assert_(np.isclose(np.inf, -np.inf) is np.False_)
+        assert_(np.isclose(0, np.inf) is np.False_)
+        assert_(type(np.isclose(0, np.inf)) is np.bool_)
+
+    def test_timedelta(self):
+        # Allclose currently works for timedelta64 as long as `atol` is
+        # an integer or also a timedelta64
+        a = np.array([[1, 2, 3, "NaT"]], dtype="m8[ns]")
+        assert np.isclose(a, a, atol=0, equal_nan=True).all()
+        assert np.isclose(a, a, atol=np.timedelta64(1, "ns"), equal_nan=True).all()
+        assert np.allclose(a, a, atol=0, equal_nan=True)
+        assert np.allclose(a, a, atol=np.timedelta64(1, "ns"), equal_nan=True)
+
+
+class TestStdVar:
+    def setup_method(self):
+        self.A = np.array([1, -1, 1, -1])
+        self.real_var = 1
+
+    def test_basic(self):
+        assert_almost_equal(np.var(self.A), self.real_var)
+        assert_almost_equal(np.std(self.A)**2, self.real_var)
+
+    def test_scalars(self):
+        assert_equal(np.var(1), 0)
+        assert_equal(np.std(1), 0)
+
+    def test_ddof1(self):
+        assert_almost_equal(np.var(self.A, ddof=1),
+                            self.real_var * len(self.A) / (len(self.A) - 1))
+        assert_almost_equal(np.std(self.A, ddof=1)**2,
+                            self.real_var*len(self.A) / (len(self.A) - 1))
+
+    def test_ddof2(self):
+        assert_almost_equal(np.var(self.A, ddof=2),
+                            self.real_var * len(self.A) / (len(self.A) - 2))
+        assert_almost_equal(np.std(self.A, ddof=2)**2,
+                            self.real_var * len(self.A) / (len(self.A) - 2))
+
+    def test_out_scalar(self):
+        d = np.arange(10)
+        out = np.array(0.)
+        r = np.std(d, out=out)
+        assert_(r is out)
+        assert_array_equal(r, out)
+        r = np.var(d, out=out)
+        assert_(r is out)
+        assert_array_equal(r, out)
+        r = np.mean(d, out=out)
+        assert_(r is out)
+        assert_array_equal(r, out)
+
+
+class TestStdVarComplex:
+    def test_basic(self):
+        A = np.array([1, 1.j, -1, -1.j])
+        real_var = 1
+        assert_almost_equal(np.var(A), real_var)
+        assert_almost_equal(np.std(A)**2, real_var)
+
+    def test_scalars(self):
+        assert_equal(np.var(1j), 0)
+        assert_equal(np.std(1j), 0)
+
+
+class TestCreationFuncs:
+    # Test ones, zeros, empty and full.
+
+    def setup_method(self):
+        dtypes = {np.dtype(tp) for tp in itertools.chain(*np.sctypes.values())}
+        # void, bytes, str
+        variable_sized = {tp for tp in dtypes if tp.str.endswith('0')}
+        self.dtypes = sorted(dtypes - variable_sized |
+                             {np.dtype(tp.str.replace("0", str(i)))
+                              for tp in variable_sized for i in range(1, 10)},
+                             key=lambda dtype: dtype.str)
+        self.orders = {'C': 'c_contiguous', 'F': 'f_contiguous'}
+        self.ndims = 10
+
+    def check_function(self, func, fill_value=None):
+        par = ((0, 1, 2),
+               range(self.ndims),
+               self.orders,
+               self.dtypes)
+        fill_kwarg = {}
+        if fill_value is not None:
+            fill_kwarg = {'fill_value': fill_value}
+
+        for size, ndims, order, dtype in itertools.product(*par):
+            shape = ndims * [size]
+
+            # do not fill void type
+            if fill_kwarg and dtype.str.startswith('|V'):
+                continue
+
+            arr = func(shape, order=order, dtype=dtype,
+                       **fill_kwarg)
+
+            assert_equal(arr.dtype, dtype)
+            assert_(getattr(arr.flags, self.orders[order]))
+
+            if fill_value is not None:
+                if dtype.str.startswith('|S'):
+                    val = str(fill_value)
+                else:
+                    val = fill_value
+                assert_equal(arr, dtype.type(val))
+
+    def test_zeros(self):
+        self.check_function(np.zeros)
+
+    def test_ones(self):
+        self.check_function(np.ones)
+
+    def test_empty(self):
+        self.check_function(np.empty)
+
+    def test_full(self):
+        self.check_function(np.full, 0)
+        self.check_function(np.full, 1)
+
+    @pytest.mark.skipif(not HAS_REFCOUNT, reason="Python lacks refcounts")
+    def test_for_reference_leak(self):
+        # Make sure we have an object for reference
+        dim = 1
+        beg = sys.getrefcount(dim)
+        np.zeros([dim]*10)
+        assert_(sys.getrefcount(dim) == beg)
+        np.ones([dim]*10)
+        assert_(sys.getrefcount(dim) == beg)
+        np.empty([dim]*10)
+        assert_(sys.getrefcount(dim) == beg)
+        np.full([dim]*10, 0)
+        assert_(sys.getrefcount(dim) == beg)
+
+
+class TestLikeFuncs:
+    '''Test ones_like, zeros_like, empty_like and full_like'''
+
+    def setup_method(self):
+        self.data = [
+                # Array scalars
+                (np.array(3.), None),
+                (np.array(3), 'f8'),
+                # 1D arrays
+                (np.arange(6, dtype='f4'), None),
+                (np.arange(6), 'c16'),
+                # 2D C-layout arrays
+                (np.arange(6).reshape(2, 3), None),
+                (np.arange(6).reshape(3, 2), 'i1'),
+                # 2D F-layout arrays
+                (np.arange(6).reshape((2, 3), order='F'), None),
+                (np.arange(6).reshape((3, 2), order='F'), 'i1'),
+                # 3D C-layout arrays
+                (np.arange(24).reshape(2, 3, 4), None),
+                (np.arange(24).reshape(4, 3, 2), 'f4'),
+                # 3D F-layout arrays
+                (np.arange(24).reshape((2, 3, 4), order='F'), None),
+                (np.arange(24).reshape((4, 3, 2), order='F'), 'f4'),
+                # 3D non-C/F-layout arrays
+                (np.arange(24).reshape(2, 3, 4).swapaxes(0, 1), None),
+                (np.arange(24).reshape(4, 3, 2).swapaxes(0, 1), '?'),
+                     ]
+        self.shapes = [(), (5,), (5,6,), (5,6,7,)]
+
+    def compare_array_value(self, dz, value, fill_value):
+        if value is not None:
+            if fill_value:
+                # Conversion is close to what np.full_like uses
+                # but we  may want to convert directly in the future
+                # which may result in errors (where this does not).
+                z = np.array(value).astype(dz.dtype)
+                assert_(np.all(dz == z))
+            else:
+                assert_(np.all(dz == value))
+
+    def check_like_function(self, like_function, value, fill_value=False):
+        if fill_value:
+            fill_kwarg = {'fill_value': value}
+        else:
+            fill_kwarg = {}
+        for d, dtype in self.data:
+            # default (K) order, dtype
+            dz = like_function(d, dtype=dtype, **fill_kwarg)
+            assert_equal(dz.shape, d.shape)
+            assert_equal(np.array(dz.strides)*d.dtype.itemsize,
+                         np.array(d.strides)*dz.dtype.itemsize)
+            assert_equal(d.flags.c_contiguous, dz.flags.c_contiguous)
+            assert_equal(d.flags.f_contiguous, dz.flags.f_contiguous)
+            if dtype is None:
+                assert_equal(dz.dtype, d.dtype)
+            else:
+                assert_equal(dz.dtype, np.dtype(dtype))
+            self.compare_array_value(dz, value, fill_value)
+
+            # C order, default dtype
+            dz = like_function(d, order='C', dtype=dtype, **fill_kwarg)
+            assert_equal(dz.shape, d.shape)
+            assert_(dz.flags.c_contiguous)
+            if dtype is None:
+                assert_equal(dz.dtype, d.dtype)
+            else:
+                assert_equal(dz.dtype, np.dtype(dtype))
+            self.compare_array_value(dz, value, fill_value)
+
+            # F order, default dtype
+            dz = like_function(d, order='F', dtype=dtype, **fill_kwarg)
+            assert_equal(dz.shape, d.shape)
+            assert_(dz.flags.f_contiguous)
+            if dtype is None:
+                assert_equal(dz.dtype, d.dtype)
+            else:
+                assert_equal(dz.dtype, np.dtype(dtype))
+            self.compare_array_value(dz, value, fill_value)
+
+            # A order
+            dz = like_function(d, order='A', dtype=dtype, **fill_kwarg)
+            assert_equal(dz.shape, d.shape)
+            if d.flags.f_contiguous:
+                assert_(dz.flags.f_contiguous)
+            else:
+                assert_(dz.flags.c_contiguous)
+            if dtype is None:
+                assert_equal(dz.dtype, d.dtype)
+            else:
+                assert_equal(dz.dtype, np.dtype(dtype))
+            self.compare_array_value(dz, value, fill_value)
+
+            # Test the 'shape' parameter
+            for s in self.shapes:
+                for o in 'CFA':
+                    sz = like_function(d, dtype=dtype, shape=s, order=o,
+                                       **fill_kwarg)
+                    assert_equal(sz.shape, s)
+                    if dtype is None:
+                        assert_equal(sz.dtype, d.dtype)
+                    else:
+                        assert_equal(sz.dtype, np.dtype(dtype))
+                    if o == 'C' or (o == 'A' and d.flags.c_contiguous):
+                        assert_(sz.flags.c_contiguous)
+                    elif o == 'F' or (o == 'A' and d.flags.f_contiguous):
+                        assert_(sz.flags.f_contiguous)
+                    self.compare_array_value(sz, value, fill_value)
+
+                if (d.ndim != len(s)):
+                    assert_equal(np.argsort(like_function(d, dtype=dtype,
+                                                          shape=s, order='K',
+                                                          **fill_kwarg).strides),
+                                 np.argsort(np.empty(s, dtype=dtype,
+                                                     order='C').strides))
+                else:
+                    assert_equal(np.argsort(like_function(d, dtype=dtype,
+                                                          shape=s, order='K',
+                                                          **fill_kwarg).strides),
+                                 np.argsort(d.strides))
+
+        # Test the 'subok' parameter
+        class MyNDArray(np.ndarray):
+            pass
+
+        a = np.array([[1, 2], [3, 4]]).view(MyNDArray)
+
+        b = like_function(a, **fill_kwarg)
+        assert_(type(b) is MyNDArray)
+
+        b = like_function(a, subok=False, **fill_kwarg)
+        assert_(type(b) is not MyNDArray)
+
+    def test_ones_like(self):
+        self.check_like_function(np.ones_like, 1)
+
+    def test_zeros_like(self):
+        self.check_like_function(np.zeros_like, 0)
+
+    def test_empty_like(self):
+        self.check_like_function(np.empty_like, None)
+
+    def test_filled_like(self):
+        self.check_like_function(np.full_like, 0, True)
+        self.check_like_function(np.full_like, 1, True)
+        self.check_like_function(np.full_like, 1000, True)
+        self.check_like_function(np.full_like, 123.456, True)
+        # Inf to integer casts cause invalid-value errors: ignore them.
+        with np.errstate(invalid="ignore"):
+            self.check_like_function(np.full_like, np.inf, True)
+
+    @pytest.mark.parametrize('likefunc', [np.empty_like, np.full_like,
+                                          np.zeros_like, np.ones_like])
+    @pytest.mark.parametrize('dtype', [str, bytes])
+    def test_dtype_str_bytes(self, likefunc, dtype):
+        # Regression test for gh-19860
+        a = np.arange(16).reshape(2, 8)
+        b = a[:, ::2]  # Ensure b is not contiguous.
+        kwargs = {'fill_value': ''} if likefunc == np.full_like else {}
+        result = likefunc(b, dtype=dtype, **kwargs)
+        if dtype == str:
+            assert result.strides == (16, 4)
+        else:
+            # dtype is bytes
+            assert result.strides == (4, 1)
+
+
+class TestCorrelate:
+    def _setup(self, dt):
+        self.x = np.array([1, 2, 3, 4, 5], dtype=dt)
+        self.xs = np.arange(1, 20)[::3]
+        self.y = np.array([-1, -2, -3], dtype=dt)
+        self.z1 = np.array([-3., -8., -14., -20., -26., -14., -5.], dtype=dt)
+        self.z1_4 = np.array([-2., -5., -8., -11., -14., -5.], dtype=dt)
+        self.z1r = np.array([-15., -22., -22., -16., -10., -4., -1.], dtype=dt)
+        self.z2 = np.array([-5., -14., -26., -20., -14., -8., -3.], dtype=dt)
+        self.z2r = np.array([-1., -4., -10., -16., -22., -22., -15.], dtype=dt)
+        self.zs = np.array([-3., -14., -30., -48., -66., -84.,
+                           -102., -54., -19.], dtype=dt)
+
+    def test_float(self):
+        self._setup(float)
+        z = np.correlate(self.x, self.y, 'full')
+        assert_array_almost_equal(z, self.z1)
+        z = np.correlate(self.x, self.y[:-1], 'full')
+        assert_array_almost_equal(z, self.z1_4)
+        z = np.correlate(self.y, self.x, 'full')
+        assert_array_almost_equal(z, self.z2)
+        z = np.correlate(self.x[::-1], self.y, 'full')
+        assert_array_almost_equal(z, self.z1r)
+        z = np.correlate(self.y, self.x[::-1], 'full')
+        assert_array_almost_equal(z, self.z2r)
+        z = np.correlate(self.xs, self.y, 'full')
+        assert_array_almost_equal(z, self.zs)
+
+    def test_object(self):
+        self._setup(Decimal)
+        z = np.correlate(self.x, self.y, 'full')
+        assert_array_almost_equal(z, self.z1)
+        z = np.correlate(self.y, self.x, 'full')
+        assert_array_almost_equal(z, self.z2)
+
+    def test_no_overwrite(self):
+        d = np.ones(100)
+        k = np.ones(3)
+        np.correlate(d, k)
+        assert_array_equal(d, np.ones(100))
+        assert_array_equal(k, np.ones(3))
+
+    def test_complex(self):
+        x = np.array([1, 2, 3, 4+1j], dtype=complex)
+        y = np.array([-1, -2j, 3+1j], dtype=complex)
+        r_z = np.array([3-1j, 6, 8+1j, 11+5j, -5+8j, -4-1j], dtype=complex)
+        r_z = r_z[::-1].conjugate()
+        z = np.correlate(y, x, mode='full')
+        assert_array_almost_equal(z, r_z)
+
+    def test_zero_size(self):
+        with pytest.raises(ValueError):
+            np.correlate(np.array([]), np.ones(1000), mode='full')
+        with pytest.raises(ValueError):
+            np.correlate(np.ones(1000), np.array([]), mode='full')
+
+    def test_mode(self):
+        d = np.ones(100)
+        k = np.ones(3)
+        default_mode = np.correlate(d, k, mode='valid')
+        with assert_warns(DeprecationWarning):
+            valid_mode = np.correlate(d, k, mode='v')
+        assert_array_equal(valid_mode, default_mode)
+        # integer mode
+        with assert_raises(ValueError):
+            np.correlate(d, k, mode=-1)
+        assert_array_equal(np.correlate(d, k, mode=0), valid_mode)
+        # illegal arguments
+        with assert_raises(TypeError):
+            np.correlate(d, k, mode=None)
+
+
+class TestConvolve:
+    def test_object(self):
+        d = [1.] * 100
+        k = [1.] * 3
+        assert_array_almost_equal(np.convolve(d, k)[2:-2], np.full(98, 3))
+
+    def test_no_overwrite(self):
+        d = np.ones(100)
+        k = np.ones(3)
+        np.convolve(d, k)
+        assert_array_equal(d, np.ones(100))
+        assert_array_equal(k, np.ones(3))
+
+    def test_mode(self):
+        d = np.ones(100)
+        k = np.ones(3)
+        default_mode = np.convolve(d, k, mode='full')
+        with assert_warns(DeprecationWarning):
+            full_mode = np.convolve(d, k, mode='f')
+        assert_array_equal(full_mode, default_mode)
+        # integer mode
+        with assert_raises(ValueError):
+            np.convolve(d, k, mode=-1)
+        assert_array_equal(np.convolve(d, k, mode=2), full_mode)
+        # illegal arguments
+        with assert_raises(TypeError):
+            np.convolve(d, k, mode=None)
+
+
+class TestArgwhere:
+
+    @pytest.mark.parametrize('nd', [0, 1, 2])
+    def test_nd(self, nd):
+        # get an nd array with multiple elements in every dimension
+        x = np.empty((2,)*nd, bool)
+
+        # none
+        x[...] = False
+        assert_equal(np.argwhere(x).shape, (0, nd))
+
+        # only one
+        x[...] = False
+        x.flat[0] = True
+        assert_equal(np.argwhere(x).shape, (1, nd))
+
+        # all but one
+        x[...] = True
+        x.flat[0] = False
+        assert_equal(np.argwhere(x).shape, (x.size - 1, nd))
+
+        # all
+        x[...] = True
+        assert_equal(np.argwhere(x).shape, (x.size, nd))
+
+    def test_2D(self):
+        x = np.arange(6).reshape((2, 3))
+        assert_array_equal(np.argwhere(x > 1),
+                           [[0, 2],
+                            [1, 0],
+                            [1, 1],
+                            [1, 2]])
+
+    def test_list(self):
+        assert_equal(np.argwhere([4, 0, 2, 1, 3]), [[0], [2], [3], [4]])
+
+
+class TestStringFunction:
+
+    def test_set_string_function(self):
+        a = np.array([1])
+        np.set_string_function(lambda x: "FOO", repr=True)
+        assert_equal(repr(a), "FOO")
+        np.set_string_function(None, repr=True)
+        assert_equal(repr(a), "array([1])")
+
+        np.set_string_function(lambda x: "FOO", repr=False)
+        assert_equal(str(a), "FOO")
+        np.set_string_function(None, repr=False)
+        assert_equal(str(a), "[1]")
+
+
+class TestRoll:
+    def test_roll1d(self):
+        x = np.arange(10)
+        xr = np.roll(x, 2)
+        assert_equal(xr, np.array([8, 9, 0, 1, 2, 3, 4, 5, 6, 7]))
+
+    def test_roll2d(self):
+        x2 = np.reshape(np.arange(10), (2, 5))
+        x2r = np.roll(x2, 1)
+        assert_equal(x2r, np.array([[9, 0, 1, 2, 3], [4, 5, 6, 7, 8]]))
+
+        x2r = np.roll(x2, 1, axis=0)
+        assert_equal(x2r, np.array([[5, 6, 7, 8, 9], [0, 1, 2, 3, 4]]))
+
+        x2r = np.roll(x2, 1, axis=1)
+        assert_equal(x2r, np.array([[4, 0, 1, 2, 3], [9, 5, 6, 7, 8]]))
+
+        # Roll multiple axes at once.
+        x2r = np.roll(x2, 1, axis=(0, 1))
+        assert_equal(x2r, np.array([[9, 5, 6, 7, 8], [4, 0, 1, 2, 3]]))
+
+        x2r = np.roll(x2, (1, 0), axis=(0, 1))
+        assert_equal(x2r, np.array([[5, 6, 7, 8, 9], [0, 1, 2, 3, 4]]))
+
+        x2r = np.roll(x2, (-1, 0), axis=(0, 1))
+        assert_equal(x2r, np.array([[5, 6, 7, 8, 9], [0, 1, 2, 3, 4]]))
+
+        x2r = np.roll(x2, (0, 1), axis=(0, 1))
+        assert_equal(x2r, np.array([[4, 0, 1, 2, 3], [9, 5, 6, 7, 8]]))
+
+        x2r = np.roll(x2, (0, -1), axis=(0, 1))
+        assert_equal(x2r, np.array([[1, 2, 3, 4, 0], [6, 7, 8, 9, 5]]))
+
+        x2r = np.roll(x2, (1, 1), axis=(0, 1))
+        assert_equal(x2r, np.array([[9, 5, 6, 7, 8], [4, 0, 1, 2, 3]]))
+
+        x2r = np.roll(x2, (-1, -1), axis=(0, 1))
+        assert_equal(x2r, np.array([[6, 7, 8, 9, 5], [1, 2, 3, 4, 0]]))
+
+        # Roll the same axis multiple times.
+        x2r = np.roll(x2, 1, axis=(0, 0))
+        assert_equal(x2r, np.array([[0, 1, 2, 3, 4], [5, 6, 7, 8, 9]]))
+
+        x2r = np.roll(x2, 1, axis=(1, 1))
+        assert_equal(x2r, np.array([[3, 4, 0, 1, 2], [8, 9, 5, 6, 7]]))
+
+        # Roll more than one turn in either direction.
+        x2r = np.roll(x2, 6, axis=1)
+        assert_equal(x2r, np.array([[4, 0, 1, 2, 3], [9, 5, 6, 7, 8]]))
+
+        x2r = np.roll(x2, -4, axis=1)
+        assert_equal(x2r, np.array([[4, 0, 1, 2, 3], [9, 5, 6, 7, 8]]))
+
+    def test_roll_empty(self):
+        x = np.array([])
+        assert_equal(np.roll(x, 1), np.array([]))
+
+
+class TestRollaxis:
+
+    # expected shape indexed by (axis, start) for array of
+    # shape (1, 2, 3, 4)
+    tgtshape = {(0, 0): (1, 2, 3, 4), (0, 1): (1, 2, 3, 4),
+                (0, 2): (2, 1, 3, 4), (0, 3): (2, 3, 1, 4),
+                (0, 4): (2, 3, 4, 1),
+                (1, 0): (2, 1, 3, 4), (1, 1): (1, 2, 3, 4),
+                (1, 2): (1, 2, 3, 4), (1, 3): (1, 3, 2, 4),
+                (1, 4): (1, 3, 4, 2),
+                (2, 0): (3, 1, 2, 4), (2, 1): (1, 3, 2, 4),
+                (2, 2): (1, 2, 3, 4), (2, 3): (1, 2, 3, 4),
+                (2, 4): (1, 2, 4, 3),
+                (3, 0): (4, 1, 2, 3), (3, 1): (1, 4, 2, 3),
+                (3, 2): (1, 2, 4, 3), (3, 3): (1, 2, 3, 4),
+                (3, 4): (1, 2, 3, 4)}
+
+    def test_exceptions(self):
+        a = np.arange(1*2*3*4).reshape(1, 2, 3, 4)
+        assert_raises(np.AxisError, np.rollaxis, a, -5, 0)
+        assert_raises(np.AxisError, np.rollaxis, a, 0, -5)
+        assert_raises(np.AxisError, np.rollaxis, a, 4, 0)
+        assert_raises(np.AxisError, np.rollaxis, a, 0, 5)
+
+    def test_results(self):
+        a = np.arange(1*2*3*4).reshape(1, 2, 3, 4).copy()
+        aind = np.indices(a.shape)
+        assert_(a.flags['OWNDATA'])
+        for (i, j) in self.tgtshape:
+            # positive axis, positive start
+            res = np.rollaxis(a, axis=i, start=j)
+            i0, i1, i2, i3 = aind[np.array(res.shape) - 1]
+            assert_(np.all(res[i0, i1, i2, i3] == a))
+            assert_(res.shape == self.tgtshape[(i, j)], str((i,j)))
+            assert_(not res.flags['OWNDATA'])
+
+            # negative axis, positive start
+            ip = i + 1
+            res = np.rollaxis(a, axis=-ip, start=j)
+            i0, i1, i2, i3 = aind[np.array(res.shape) - 1]
+            assert_(np.all(res[i0, i1, i2, i3] == a))
+            assert_(res.shape == self.tgtshape[(4 - ip, j)])
+            assert_(not res.flags['OWNDATA'])
+
+            # positive axis, negative start
+            jp = j + 1 if j < 4 else j
+            res = np.rollaxis(a, axis=i, start=-jp)
+            i0, i1, i2, i3 = aind[np.array(res.shape) - 1]
+            assert_(np.all(res[i0, i1, i2, i3] == a))
+            assert_(res.shape == self.tgtshape[(i, 4 - jp)])
+            assert_(not res.flags['OWNDATA'])
+
+            # negative axis, negative start
+            ip = i + 1
+            jp = j + 1 if j < 4 else j
+            res = np.rollaxis(a, axis=-ip, start=-jp)
+            i0, i1, i2, i3 = aind[np.array(res.shape) - 1]
+            assert_(np.all(res[i0, i1, i2, i3] == a))
+            assert_(res.shape == self.tgtshape[(4 - ip, 4 - jp)])
+            assert_(not res.flags['OWNDATA'])
+
+
+class TestMoveaxis:
+    def test_move_to_end(self):
+        x = np.random.randn(5, 6, 7)
+        for source, expected in [(0, (6, 7, 5)),
+                                 (1, (5, 7, 6)),
+                                 (2, (5, 6, 7)),
+                                 (-1, (5, 6, 7))]:
+            actual = np.moveaxis(x, source, -1).shape
+            assert_(actual, expected)
+
+    def test_move_new_position(self):
+        x = np.random.randn(1, 2, 3, 4)
+        for source, destination, expected in [
+                (0, 1, (2, 1, 3, 4)),
+                (1, 2, (1, 3, 2, 4)),
+                (1, -1, (1, 3, 4, 2)),
+                ]:
+            actual = np.moveaxis(x, source, destination).shape
+            assert_(actual, expected)
+
+    def test_preserve_order(self):
+        x = np.zeros((1, 2, 3, 4))
+        for source, destination in [
+                (0, 0),
+                (3, -1),
+                (-1, 3),
+                ([0, -1], [0, -1]),
+                ([2, 0], [2, 0]),
+                (range(4), range(4)),
+                ]:
+            actual = np.moveaxis(x, source, destination).shape
+            assert_(actual, (1, 2, 3, 4))
+
+    def test_move_multiples(self):
+        x = np.zeros((0, 1, 2, 3))
+        for source, destination, expected in [
+                ([0, 1], [2, 3], (2, 3, 0, 1)),
+                ([2, 3], [0, 1], (2, 3, 0, 1)),
+                ([0, 1, 2], [2, 3, 0], (2, 3, 0, 1)),
+                ([3, 0], [1, 0], (0, 3, 1, 2)),
+                ([0, 3], [0, 1], (0, 3, 1, 2)),
+                ]:
+            actual = np.moveaxis(x, source, destination).shape
+            assert_(actual, expected)
+
+    def test_errors(self):
+        x = np.random.randn(1, 2, 3)
+        assert_raises_regex(np.AxisError, 'source.*out of bounds',
+                            np.moveaxis, x, 3, 0)
+        assert_raises_regex(np.AxisError, 'source.*out of bounds',
+                            np.moveaxis, x, -4, 0)
+        assert_raises_regex(np.AxisError, 'destination.*out of bounds',
+                            np.moveaxis, x, 0, 5)
+        assert_raises_regex(ValueError, 'repeated axis in `source`',
+                            np.moveaxis, x, [0, 0], [0, 1])
+        assert_raises_regex(ValueError, 'repeated axis in `destination`',
+                            np.moveaxis, x, [0, 1], [1, 1])
+        assert_raises_regex(ValueError, 'must have the same number',
+                            np.moveaxis, x, 0, [0, 1])
+        assert_raises_regex(ValueError, 'must have the same number',
+                            np.moveaxis, x, [0, 1], [0])
+
+    def test_array_likes(self):
+        x = np.ma.zeros((1, 2, 3))
+        result = np.moveaxis(x, 0, 0)
+        assert_(x.shape, result.shape)
+        assert_(isinstance(result, np.ma.MaskedArray))
+
+        x = [1, 2, 3]
+        result = np.moveaxis(x, 0, 0)
+        assert_(x, list(result))
+        assert_(isinstance(result, np.ndarray))
+
+
+class TestCross:
+    def test_2x2(self):
+        u = [1, 2]
+        v = [3, 4]
+        z = -2
+        cp = np.cross(u, v)
+        assert_equal(cp, z)
+        cp = np.cross(v, u)
+        assert_equal(cp, -z)
+
+    def test_2x3(self):
+        u = [1, 2]
+        v = [3, 4, 5]
+        z = np.array([10, -5, -2])
+        cp = np.cross(u, v)
+        assert_equal(cp, z)
+        cp = np.cross(v, u)
+        assert_equal(cp, -z)
+
+    def test_3x3(self):
+        u = [1, 2, 3]
+        v = [4, 5, 6]
+        z = np.array([-3, 6, -3])
+        cp = np.cross(u, v)
+        assert_equal(cp, z)
+        cp = np.cross(v, u)
+        assert_equal(cp, -z)
+
+    def test_broadcasting(self):
+        # Ticket #2624 (Trac #2032)
+        u = np.tile([1, 2], (11, 1))
+        v = np.tile([3, 4], (11, 1))
+        z = -2
+        assert_equal(np.cross(u, v), z)
+        assert_equal(np.cross(v, u), -z)
+        assert_equal(np.cross(u, u), 0)
+
+        u = np.tile([1, 2], (11, 1)).T
+        v = np.tile([3, 4, 5], (11, 1))
+        z = np.tile([10, -5, -2], (11, 1))
+        assert_equal(np.cross(u, v, axisa=0), z)
+        assert_equal(np.cross(v, u.T), -z)
+        assert_equal(np.cross(v, v), 0)
+
+        u = np.tile([1, 2, 3], (11, 1)).T
+        v = np.tile([3, 4], (11, 1)).T
+        z = np.tile([-12, 9, -2], (11, 1))
+        assert_equal(np.cross(u, v, axisa=0, axisb=0), z)
+        assert_equal(np.cross(v.T, u.T), -z)
+        assert_equal(np.cross(u.T, u.T), 0)
+
+        u = np.tile([1, 2, 3], (5, 1))
+        v = np.tile([4, 5, 6], (5, 1)).T
+        z = np.tile([-3, 6, -3], (5, 1))
+        assert_equal(np.cross(u, v, axisb=0), z)
+        assert_equal(np.cross(v.T, u), -z)
+        assert_equal(np.cross(u, u), 0)
+
+    def test_broadcasting_shapes(self):
+        u = np.ones((2, 1, 3))
+        v = np.ones((5, 3))
+        assert_equal(np.cross(u, v).shape, (2, 5, 3))
+        u = np.ones((10, 3, 5))
+        v = np.ones((2, 5))
+        assert_equal(np.cross(u, v, axisa=1, axisb=0).shape, (10, 5, 3))
+        assert_raises(np.AxisError, np.cross, u, v, axisa=1, axisb=2)
+        assert_raises(np.AxisError, np.cross, u, v, axisa=3, axisb=0)
+        u = np.ones((10, 3, 5, 7))
+        v = np.ones((5, 7, 2))
+        assert_equal(np.cross(u, v, axisa=1, axisc=2).shape, (10, 5, 3, 7))
+        assert_raises(np.AxisError, np.cross, u, v, axisa=-5, axisb=2)
+        assert_raises(np.AxisError, np.cross, u, v, axisa=1, axisb=-4)
+        # gh-5885
+        u = np.ones((3, 4, 2))
+        for axisc in range(-2, 2):
+            assert_equal(np.cross(u, u, axisc=axisc).shape, (3, 4))
+
+    def test_uint8_int32_mixed_dtypes(self):
+        # regression test for gh-19138
+        u = np.array([[195, 8, 9]], np.uint8)
+        v = np.array([250, 166, 68], np.int32)
+        z = np.array([[950, 11010, -30370]], dtype=np.int32)
+        assert_equal(np.cross(v, u), z)
+        assert_equal(np.cross(u, v), -z)
+
+
+def test_outer_out_param():
+    arr1 = np.ones((5,))
+    arr2 = np.ones((2,))
+    arr3 = np.linspace(-2, 2, 5)
+    out1 = np.ndarray(shape=(5,5))
+    out2 = np.ndarray(shape=(2, 5))
+    res1 = np.outer(arr1, arr3, out1)
+    assert_equal(res1, out1)
+    assert_equal(np.outer(arr2, arr3, out2), out2)
+
+
+class TestIndices:
+
+    def test_simple(self):
+        [x, y] = np.indices((4, 3))
+        assert_array_equal(x, np.array([[0, 0, 0],
+                                        [1, 1, 1],
+                                        [2, 2, 2],
+                                        [3, 3, 3]]))
+        assert_array_equal(y, np.array([[0, 1, 2],
+                                        [0, 1, 2],
+                                        [0, 1, 2],
+                                        [0, 1, 2]]))
+
+    def test_single_input(self):
+        [x] = np.indices((4,))
+        assert_array_equal(x, np.array([0, 1, 2, 3]))
+
+        [x] = np.indices((4,), sparse=True)
+        assert_array_equal(x, np.array([0, 1, 2, 3]))
+
+    def test_scalar_input(self):
+        assert_array_equal([], np.indices(()))
+        assert_array_equal([], np.indices((), sparse=True))
+        assert_array_equal([[]], np.indices((0,)))
+        assert_array_equal([[]], np.indices((0,), sparse=True))
+
+    def test_sparse(self):
+        [x, y] = np.indices((4,3), sparse=True)
+        assert_array_equal(x, np.array([[0], [1], [2], [3]]))
+        assert_array_equal(y, np.array([[0, 1, 2]]))
+
+    @pytest.mark.parametrize("dtype", [np.int32, np.int64, np.float32, np.float64])
+    @pytest.mark.parametrize("dims", [(), (0,), (4, 3)])
+    def test_return_type(self, dtype, dims):
+        inds = np.indices(dims, dtype=dtype)
+        assert_(inds.dtype == dtype)
+
+        for arr in np.indices(dims, dtype=dtype, sparse=True):
+            assert_(arr.dtype == dtype)
+
+
+class TestRequire:
+    flag_names = ['C', 'C_CONTIGUOUS', 'CONTIGUOUS',
+                  'F', 'F_CONTIGUOUS', 'FORTRAN',
+                  'A', 'ALIGNED',
+                  'W', 'WRITEABLE',
+                  'O', 'OWNDATA']
+
+    def generate_all_false(self, dtype):
+        arr = np.zeros((2, 2), [('junk', 'i1'), ('a', dtype)])
+        arr.setflags(write=False)
+        a = arr['a']
+        assert_(not a.flags['C'])
+        assert_(not a.flags['F'])
+        assert_(not a.flags['O'])
+        assert_(not a.flags['W'])
+        assert_(not a.flags['A'])
+        return a
+
+    def set_and_check_flag(self, flag, dtype, arr):
+        if dtype is None:
+            dtype = arr.dtype
+        b = np.require(arr, dtype, [flag])
+        assert_(b.flags[flag])
+        assert_(b.dtype == dtype)
+
+        # a further call to np.require ought to return the same array
+        # unless OWNDATA is specified.
+        c = np.require(b, None, [flag])
+        if flag[0] != 'O':
+            assert_(c is b)
+        else:
+            assert_(c.flags[flag])
+
+    def test_require_each(self):
+
+        id = ['f8', 'i4']
+        fd = [None, 'f8', 'c16']
+        for idtype, fdtype, flag in itertools.product(id, fd, self.flag_names):
+            a = self.generate_all_false(idtype)
+            self.set_and_check_flag(flag, fdtype,  a)
+
+    def test_unknown_requirement(self):
+        a = self.generate_all_false('f8')
+        assert_raises(KeyError, np.require, a, None, 'Q')
+
+    def test_non_array_input(self):
+        a = np.require([1, 2, 3, 4], 'i4', ['C', 'A', 'O'])
+        assert_(a.flags['O'])
+        assert_(a.flags['C'])
+        assert_(a.flags['A'])
+        assert_(a.dtype == 'i4')
+        assert_equal(a, [1, 2, 3, 4])
+
+    def test_C_and_F_simul(self):
+        a = self.generate_all_false('f8')
+        assert_raises(ValueError, np.require, a, None, ['C', 'F'])
+
+    def test_ensure_array(self):
+        class ArraySubclass(np.ndarray):
+            pass
+
+        a = ArraySubclass((2, 2))
+        b = np.require(a, None, ['E'])
+        assert_(type(b) is np.ndarray)
+
+    def test_preserve_subtype(self):
+        class ArraySubclass(np.ndarray):
+            pass
+
+        for flag in self.flag_names:
+            a = ArraySubclass((2, 2))
+            self.set_and_check_flag(flag, None, a)
+
+
+class TestBroadcast:
+    def test_broadcast_in_args(self):
+        # gh-5881
+        arrs = [np.empty((6, 7)), np.empty((5, 6, 1)), np.empty((7,)),
+                np.empty((5, 1, 7))]
+        mits = [np.broadcast(*arrs),
+                np.broadcast(np.broadcast(*arrs[:0]), np.broadcast(*arrs[0:])),
+                np.broadcast(np.broadcast(*arrs[:1]), np.broadcast(*arrs[1:])),
+                np.broadcast(np.broadcast(*arrs[:2]), np.broadcast(*arrs[2:])),
+                np.broadcast(arrs[0], np.broadcast(*arrs[1:-1]), arrs[-1])]
+        for mit in mits:
+            assert_equal(mit.shape, (5, 6, 7))
+            assert_equal(mit.ndim, 3)
+            assert_equal(mit.nd, 3)
+            assert_equal(mit.numiter, 4)
+            for a, ia in zip(arrs, mit.iters):
+                assert_(a is ia.base)
+
+    def test_broadcast_single_arg(self):
+        # gh-6899
+        arrs = [np.empty((5, 6, 7))]
+        mit = np.broadcast(*arrs)
+        assert_equal(mit.shape, (5, 6, 7))
+        assert_equal(mit.ndim, 3)
+        assert_equal(mit.nd, 3)
+        assert_equal(mit.numiter, 1)
+        assert_(arrs[0] is mit.iters[0].base)
+
+    def test_number_of_arguments(self):
+        arr = np.empty((5,))
+        for j in range(35):
+            arrs = [arr] * j
+            if j > 32:
+                assert_raises(ValueError, np.broadcast, *arrs)
+            else:
+                mit = np.broadcast(*arrs)
+                assert_equal(mit.numiter, j)
+
+    def test_broadcast_error_kwargs(self):
+        #gh-13455
+        arrs = [np.empty((5, 6, 7))]
+        mit  = np.broadcast(*arrs)
+        mit2 = np.broadcast(*arrs, **{})
+        assert_equal(mit.shape, mit2.shape)
+        assert_equal(mit.ndim, mit2.ndim)
+        assert_equal(mit.nd, mit2.nd)
+        assert_equal(mit.numiter, mit2.numiter)
+        assert_(mit.iters[0].base is mit2.iters[0].base)
+
+        assert_raises(ValueError, np.broadcast, 1, **{'x': 1})
+
+    def test_shape_mismatch_error_message(self):
+        with pytest.raises(ValueError, match=r"arg 0 with shape \(1, 3\) and "
+                                             r"arg 2 with shape \(2,\)"):
+            np.broadcast([[1, 2, 3]], [[4], [5]], [6, 7])
+
+
+class TestKeepdims:
+
+    class sub_array(np.ndarray):
+        def sum(self, axis=None, dtype=None, out=None):
+            return np.ndarray.sum(self, axis, dtype, out, keepdims=True)
+
+    def test_raise(self):
+        sub_class = self.sub_array
+        x = np.arange(30).view(sub_class)
+        assert_raises(TypeError, np.sum, x, keepdims=True)
+
+
+class TestTensordot:
+
+    def test_zero_dimension(self):
+        # Test resolution to issue #5663
+        a = np.ndarray((3,0))
+        b = np.ndarray((0,4))
+        td = np.tensordot(a, b, (1, 0))
+        assert_array_equal(td, np.dot(a, b))
+        assert_array_equal(td, np.einsum('ij,jk', a, b))
+
+    def test_zero_dimensional(self):
+        # gh-12130
+        arr_0d = np.array(1)
+        ret = np.tensordot(arr_0d, arr_0d, ([], []))  # contracting no axes is well defined
+        assert_array_equal(ret, arr_0d)