Add tests for headers

* Add tests to check for validity of the headers
* Add stubs for the tests

2 files changed, 15 insertions, 3 deletions

diff --git a/quality_control/errors.py b/quality_control/errors.py
index 961ce8e..a77039b 100644
--- a/quality_control/errors.py
+++ b/quality_control/errors.py
@@ -3,6 +3,11 @@
 class InvalidValue(Exception):
     """Raised when a function encounters an invalid value"""
 
-    def __init__(self, args):
-        Exception.__init__(self, args)
-        
+    def __init__(self, *args):
+        Exception.__init__(self, *args)
+
+class InvalidHeaderValue(Exception):
+    """Raised when a header contains values not in the reference file."""
+
+    def __init__(self, *args):
+        Exception.__init__(self, *args)
diff --git a/quality_control/headers.py b/quality_control/headers.py
new file mode 100644
index 0000000..b8ff160
--- /dev/null
+++ b/quality_control/headers.py
@@ -0,0 +1,7 @@
+"""Validate the headers"""
+
+from quality_control.errors import InvalidHeaderValue
+
+def valid_header(strains, headers):
+    "Return the valid headers with reference to strains or throw an error"
+    return None