Copy git tooling into testing_support.

testing_support/git/unittest_helpers.py

Index: testing_support/git/unittest_helpers.py
diff --git a/testing_support/git/unittest_helpers.py b/testing_support/git/unittest_helpers.py
new file mode 100644
index 0000000000000000000000000000000000000000..0ac27bd6eaff996e6e29dbd9a9d7d3a18d0ff283
--- /dev/null
+++ b/testing_support/git/unittest_helpers.py
@@ -0,0 +1,81 @@
+# 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.
+
+import unittest
+
+
+from testing_support.git.repo import GitRepo
+from testing_support.git.schema import GitRepoSchema
+
+
+class GitRepoSchemaTestBase(unittest.TestCase):
+  """A TestCase with a built-in GitRepoSchema.
+
+  Expects a class variable REPO_SCHEMA to be a GitRepoSchema string in the form
+  described by that class.
+
+  You may also set class variables in the form COMMIT_%(commit_name)s, which
+  provide the content for the given commit_name commits.
+
+  You probably will end up using either GitRepoReadOnlyTestBase or
+  GitRepoReadWriteTestBase for real tests.
+  """
+  REPO_SCHEMA = None
+
+  @classmethod
+  def getRepoContent(cls, commit):
+    return getattr(cls, 'COMMIT_%s' % commit, None)
+
+  @classmethod
+  def setUpClass(cls):
+    super(GitRepoSchemaTestBase, cls).setUpClass()
+    assert cls.REPO_SCHEMA is not None
+    cls.r_schema = GitRepoSchema(cls.REPO_SCHEMA, cls.getRepoContent)
+
+
+class GitRepoReadOnlyTestBase(GitRepoSchemaTestBase):
+  """Injects a GitRepo object given the schema and content from
+  GitRepoSchemaTestBase into TestCase classes which subclass this.
+
+  This GitRepo will appear as self.repo, and will be deleted and recreated once
+  for the duration of all the tests in the subclass.
+  """
+  REPO_SCHEMA = None
+
+  @classmethod
+  def setUpClass(cls):
+    super(GitRepoReadOnlyTestBase, cls).setUpClass()
+    assert cls.REPO_SCHEMA is not None
+    cls.repo = GitRepo(cls.r_schema)
+
+  def setUp(self):
+    self.repo.git('checkout', '-f', self.repo.last_commit)
+
+  @classmethod
+  def tearDownClass(cls):
+    cls.repo.nuke()
+    super(GitRepoReadOnlyTestBase, cls).tearDownClass()
+
+
+class GitRepoReadWriteTestBase(GitRepoSchemaTestBase):
+  """Injects a GitRepo object given the schema and content from
+  GitRepoSchemaTestBase into TestCase classes which subclass this.
+
+  This GitRepo will appear as self.repo, and will be deleted and recreated for
+  each test function in the subclass.
+  """
+  REPO_SCHEMA = None
+
+  def setUp(self):
+    super(GitRepoReadWriteTestBase, self).setUp()
+    self.repo = GitRepo(self.r_schema)
+
+  def tearDown(self):
+    self.repo.nuke()
+    super(GitRepoReadWriteTestBase, self).tearDown()
+
+  def assertSchema(self, schema_string):
+    self.assertEqual(GitRepoSchema(schema_string).simple_graph(),
+                     self.repo.to_schema().simple_graph())
+