Add tests for headers

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

1 files changed, 8 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)