Allow extensions to register serializers

Setting output_format must happen after extensions are loaded. Only in that
way can an extension register a serializer so that it will then be available
to be used with the output_format keyword. A test has been added to avoid
this regression from happening again in the future.

Fixes #238, partially reverses commit 41cc055 and provides a better fix for

1 files changed, 18 insertions, 0 deletions

diff --git a/tests/test_apis.py b/tests/test_apis.py
index 4a7c7c7..bbe165d 100644
--- a/tests/test_apis.py
+++ b/tests/test_apis.py
@@ -358,6 +358,24 @@ class testSerializers(unittest.TestCase):
                     '<MixedCase>not valid <EMPHASIS>html</EMPHASIS><HR /></MixedCase>')
 
 
+    def buildExtension(self):
+        """ Build an extension which registers fakeSerializer. """
+        def fakeSerializer(elem):
+            # Ignore input and return hardcoded output
+            return '<div><p>foo</p></div>'
+
+        class registerFakeSerializer(markdown.extensions.Extension):
+            def extendMarkdown(self, md, md_globals):
+                md.output_formats['fake'] = fakeSerializer
+
+        return registerFakeSerializer()
+
+    def testRegisterSerializer(self):
+        self.assertEqual(markdown.markdown('baz', 
+                extensions=[self.buildExtension()], output_format='fake'),
+                    '<p>foo</p>')
+
+
 class testAtomicString(unittest.TestCase):
     """ Test that AtomicStrings are honored (not parsed). """