Refactor infra git libs and testing.

infra/libs/git2/test/ref_test.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from infra.libs import git2
+from infra.libs.git2.test import test_util
+
+
+class TestRef(test_util.TestBasis):
+  def testComparison(self):
+    r = self.mkRepo()
+    O = r['refs/heads/branch_O']
+    self.assertEqual(O, O)
+    self.assertEqual(O, r['refs/heads/branch_O'])
+
+    N = r['refs/heads/branch_K']
+    self.assertNotEqual(O, N)
+
+  def testRepr(self):
+    r = self.mkRepo()
+    O = r['refs/heads/branch_O']
+    self.assertEqual("Ref(%r, 'refs/heads/branch_O')" % r, repr(O))
+
+  def testCommit(self):
+    r = self.mkRepo()
+    self.assertEqual(
+        r['refs/heads/branch_O'].commit.hsh,
+        self.repo['O'])
+
+  def testCommitBogus(self):
+    r = self.mkRepo()
+    self.assertIs(r['refs/heads/bogus'].commit, git2.INVALID)
+    # exercise __ne__ and __eq__
+    self.assertNotEqual(r['refs/heads/bogus'].commit,
+                        r['refs/heads/other_bogus'].commit)
+    self.assertFalse(r['refs/heads/bogus'].commit ==
+                     r['refs/heads/other_bogus'].commit)
+
+  def testTo(self):
+    r = self.mkRepo()
+    A = r['refs/heads/root_A']
+    O = r['refs/heads/branch_O']
+    self.assertEqual(
+        list(c.hsh for c in A.to(O)),
+        [self.repo[c] for c in 'BCDLMNO']
+    )
+
+  def testNonFastForward(self):
+    r = self.mkRepo()
+    O = r['refs/heads/branch_O']
+    D = r.get_commit(self.repo['D'])
+    with self.assertRaises(git2.CalledProcessError):
+      O.fast_forward_push(D)
+    self.assertEqual(
+        self.repo.git('rev-parse', 'branch_O').stdout.strip(),
+        self.repo['O'])
+
+  def testFastForward(self):
+    r = self.mkRepo()
+    O = r['refs/heads/branch_O']
+    S = r.get_commit(self.repo['S'])
+    self.capture_stdio(O.fast_forward_push, S)
+    self.assertEqual(O.commit.hsh, self.repo['S'])
+    self.assertEqual(
+        self.repo.git('rev-parse', 'branch_O').stdout.strip(),
+        self.repo['S'])
+
+