TEST: Move special case header equality check into TestSerializableImageAPI

Author: effigies

nibabel/tests/test_filebasedimages.py

@@ -87,6 +87,12 @@ def obj_params(self):
 class TestSerializableImageAPI(TestFBImageAPI, SerializeMixin):
     image_maker = SerializableNumpyImage
 
+    @staticmethod
+    def _header_eq(header_a, header_b):
+        """ FileBasedHeader is an abstract class, so __eq__ is undefined.
+        Checking for the same header type is sufficient, here. """
+        return type(header_a) == type(header_b) == FileBasedHeader
+
 
 def test_filebased_header():
     # Test stuff about the default FileBasedHeader

nibabel/tests/test_image_api.py

@@ -545,19 +545,13 @@ def validate_to_from_bytes(self, imaker, params):
 
     @staticmethod
     def _header_eq(header_a, header_b):
-        """ Quick-and-dirty header equality check
+        """ Header equality check that can be overridden by a subclass of this test
 
-        Abstract classes may have undefined equality, in which case test for
-        same type
+        This allows us to retain the same tests above when testing an image that uses an
+        abstract class as a header, namely when testing the FileBasedImage API, which
+        raises a NotImplementedError for __eq__
         """
-        not_implemented = False
-        header_eq = True
-        try:
-            header_eq = header_a == header_b
-        except NotImplementedError:
-            header_eq = type(header_a) == type(header_b)
-
-        return header_eq
+        return header_a == header_b