Make git unittest_helpers only use setUp/tearDown.

testing_support/git/unittest_helpers.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 testing_support import auto_stub
 
 from testing_support.git.repo import GitRepo
 from testing_support.git.schema import GitRepoSchema
 
 
-class GitRepoSchemaTestBase(auto_stub.TestCase):
-  """A TestCase with a built-in GitRepoSchema.
+class GitRepoTestBase(auto_stub.TestCase):
+  """A TestCase with a built-in GitRepoSchema and a GitRepo based on that
+  schema.
 
   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.
+  provide the content for the given commit_name commits (this behavior can be
+  overridden by overriding getRepoContent()).
 
-  You probably will end up using either GitRepoReadOnlyTestBase or
-  GitRepoReadWriteTestBase for real tests.
+  This GitRepo will appear as self.repo, and will be deleted and recreated for
+  each test method in the subclass.
   """
   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())
 
+  def setUp(self):
+    super(GitRepoTestBase, self).setUp()
+    assert self.REPO_SCHEMA is not None
+    # TODO(iannucci): r_schema could be established at class-load time, using
+    # a metaclass. This would enable us to only parse the schema once per
+    # derived test case class.
+    self.r_schema = GitRepoSchema(self.REPO_SCHEMA, self.getRepoContent)
+    self.repo = GitRepo(self.r_schema)
+    self.repo.git('checkout', '-f', self.repo.last_commit)
+
+  def tearDown(self):
+    try:
+      self.repo.nuke()
+    finally:
+      super(GitRepoTestBase, self).tearDown()
+
+
+# The read-only version used to set up and tear down repo on a setUpClass basis,
+# and the read-write version used to do it on a setUp basis. This is no longer
+# the case. Keep the names around, but they're deprecated.
+GitRepoReadWriteTestBase = GitRepoTestBase
+GitRepoReadOnlyTestBase = GitRepoTestBase
+
+# Additionally, there was a schema-only version, but it was pretty useless
+GitRepoSchemaTestBase = GitRepoTestBase