Improved performance of rev-parse test.

Hoping to make this significantly faster on travis.

Related to #245

Author: Byron

git/test/test_repo.py

@@ -34,7 +34,10 @@
 from git.util import join_path_native
 from git.exc import BadObject
 from gitdb.util import bin_to_hex
-from git.compat import string_types
+from git.compat import (
+    string_types,
+    # PY3
+)
 from gitdb.test.lib import with_rw_directory
 
 import os
@@ -555,7 +558,7 @@ def test_rev_parse(self):
         # start from reference
         num_resolved = 0
 
-        for ref in Reference.iter_items(self.rorepo):
+        for ref_no, ref in enumerate(Reference.iter_items(self.rorepo)):
             path_tokens = ref.path.split("/")
             for pt in range(len(path_tokens)):
                 path_section = '/'.join(path_tokens[-(pt + 1):])
@@ -569,6 +572,8 @@ def test_rev_parse(self):
                     pass
                 # END exception handling
             # END for each token
+            if ref_no == 3 - 1:
+                break
         # END for each reference
         assert num_resolved
 
@@ -610,6 +615,7 @@ def test_rev_parse(self):
         # END handle multiple tokens
 
         # try partial parsing
+        # if not (PY3 and 'TRAVIS' in os.environ):
         max_items = 40
         for i, binsha in enumerate(self.rorepo.odb.sha_iter()):
             assert rev_parse(bin_to_hex(binsha)[:8 - (i % 2)].decode('ascii')).binsha == binsha
@@ -618,6 +624,7 @@ def test_rev_parse(self):
                 # which requires accessing packs, it has some additional overhead
                 break
         # END for each binsha in repo
+        # end travis special handling
 
         # missing closing brace commit^{tree
         self.failUnlessRaises(ValueError, rev_parse, '0.1.4^{tree')