# HG changeset patch
# User Jeff Hammel <jhammel@mozilla.com>
# Date 1307930475 25200
# Node ID 7a11a25da2e8c4ae398cbf0caf0d786336c5daee
# Parent  f3878c2f7032c058016b413d38a6febdb16630c0
better assertion message

diff -r f3878c2f7032 -r 7a11a25da2e8 buttercup/source.py
--- a/buttercup/source.py	Sun Jun 12 18:46:05 2011 -0700
+++ b/buttercup/source.py	Sun Jun 12 19:01:15 2011 -0700
@@ -36,7 +36,8 @@
     def update(self):
         """updates a checkout or does one if it does not exist"""
         if os.path.exists(self.directory()):
-            assert os.path.exists(os.path.join(self.directory(), '.hg'))
+            hgdir = os.path.join(self.directory(), '.hg'))
+            assert os.path.exists(hgdir), "Not an hg directory: %s" % hgdir
             call(['hg', 'pull'], cwd=self.directory())
             call(['hg', 'update'], cwd=self.directory())
         else: