Enable test_post*

This requires some updating of how merger data construction gets
handled between Refs and Changes.

Change-Id: Icd81a95565ab137b98d6a8ac52e262487d412534
Story: 2000773
Task: 3389
diff --git a/tests/base.py b/tests/base.py
index b343655..af239ad 100755
--- a/tests/base.py
+++ b/tests/base.py
@@ -477,6 +477,9 @@
     def getGitUrl(self, project):
         return os.path.join(self.upstream_root, project.name)
 
+    def _getGitwebUrl(self, project, sha=None):
+        return self.getGitwebUrl(project, sha)
+
 
 class BuildHistory(object):
     def __init__(self, **kw):