Add test for duplicate headers

2 files changed, 17 insertions, 1 deletions

diff --git a/quality_control/errors.py b/quality_control/errors.py
index 758a300..993748c 100644
--- a/quality_control/errors.py
+++ b/quality_control/errors.py
@@ -12,6 +12,12 @@ class InvalidHeaderValue(Exception):
     def __init__(self, *args):
         super().__init__(self, *args)
 
+class DuplicateHeader(Exception):
+    """Raised when a header contains 2 similar headers."""
+
+    def __init__(self, *args):
+        super().__init__(self, *args)
+
 class ParseError(Exception):
     def __init(self, *args):
         super().__init__(*args)
diff --git a/tests/qc/test_header.py b/tests/qc/test_header.py
index 2feac19..a474834 100644
--- a/tests/qc/test_header.py
+++ b/tests/qc/test_header.py
@@ -3,7 +3,7 @@ from hypothesis import given
 from hypothesis import strategies as st
 
 from quality_control.headers import valid_header
-from quality_control.errors import InvalidHeaderValue
+from quality_control.errors import DuplicateHeader, InvalidHeaderValue
 
 @given(headers=st.lists(st.text(max_size=10)))
 def test_valid_header_errors_with_invalid_headers(headers):
@@ -19,3 +19,13 @@ def test_valid_header_errors_with_invalid_headers(headers):
 def test_valid_header_strains_passes_with_valid_headers(strains, headers):
     "Verify that the check for header validity works"
     assert valid_header(strains, headers)
+
+@pytest.mark.parametrize(
+    "strains,headers", [
+        (("BXD1", "BXD2", "BXD3"), ("ProbeSet", "BXD3", "BXD1", "BXD1")),
+        (("AStrain", "AnotherStrain", "YetAnotherStrain"),
+         ("Individual", "AStrain", "AnotherStrain", "YetAnotherStrain",
+          "AStrain"))])
+def test_valid_header_fails_with_duplicate_headers(strains, headers):
+    with pytest.raises(DuplicateHeader):
+        valid_header(strains, headers)