As a special case, view_for_mimetype returns the view list if the request param is None.

Tests updated.

kepi/tophat_ui/tests/test_view_for_mimetype.py

@@ -112,3 +112,31 @@ class Tests(TestCase):
                 vfm(DummyRequest('image/jpeg'), '123'),
                 'df123',
                 )
+
+    def test_passing_None(self):
+
+        def th():
+            pass
+
+        def aj():
+            pass
+
+        def df():
+            pass
+
+        vfm = view_for_mimetype(
+                [
+                    ('text', 'html', th),
+                    ('application', 'json', aj),
+                    ],
+                default = df,
+                )
+
+        self.assertEqual(
+                vfm(None),
+                [
+                    ('text', 'html', th),
+                    ('application', 'json', aj),
+                    (None, None, df),
+                    ],
+                )

kepi/tophat_ui/view_for_mimetype.py

@@ -31,6 +31,9 @@ def view_for_mimetype(
     If you don't give a default, the view function returns
     a new HttpResponse with status_code==406, i.e. "Not Acceptable".
     See: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/406
+
+    As a special case, if request is None, returns the list of views.
+    A default value will be at the end, with type and subtype set to None.
     """
 
     def _view_for_mimetype_inner(
@@ -38,6 +41,14 @@ def view_for_mimetype(
             *args, **kwargs,
             ):
 
+        if request is None:
+            result = views.copy()
+
+            if default is not None:
+                result.append((None, None, default))
+
+            return result
+
         accept_header = request.headers.get('Accept', '')
         accept_parsed = parse_accept_header(accept_header)