Fix broken unit tests caused by CheckVersion() change.

feedvalidator.py

@@ -601,15 +601,14 @@ def RunValidation(feed, options, problems):
     return schedule, 0, other_problems_string
 
 
-def CheckVersion(latest_version=''):
+def CheckVersion(latest_version=None):
   """
   Check there is newer version of this project.
 
   Codes are based on http://www.voidspace.org.uk/python/articles/urllib2.shtml
   Already got permission from the copyright holder.
   """
   current_version = transitfeed.__version__
-  latest_version = None
   if not latest_version:
     timeout = 20
     socket.setdefaulttimeout(timeout)

test/testfeedvalidator.py

@@ -466,9 +466,7 @@ def testEmptyIsReturned(self):
 class MockURLOpen:
   """Pretend to be a urllib2.urlopen suitable for testing."""
   def mockedConnectSuccess(self, request):
-    return StringIO.StringIO('<li><a href="transitfeed-1.0.0/">transitfeed-'
-                             '1.0.0/</a></li><li><a href=transitfeed-100.0.1/>'
-                             'transitfeed-100.0.1/</a></li>')
+    return StringIO.StringIO('latest_version=100.0.1')
 
   def mockedPageNotFound(self, request):
     raise HTTPError(request.get_full_url(), 404, 'Not Found',