[Culprit-finder] Refactor findit testcase and move it to libs.

appengine/findit/crash/test/crash_testcase.py

Index: appengine/findit/crash/test/crash_testcase.py
diff --git a/appengine/findit/crash/test/crash_testcase.py b/appengine/findit/crash/test/crash_testcase.py
index 79ac67fd3c77d58f6343d0aedeff7f3fd468ec57..2d6857afeb224b778ea7ebcdf6ac7ce4d333d6a6 100644
--- a/appengine/findit/crash/test/crash_testcase.py
+++ b/appengine/findit/crash/test/crash_testcase.py
@@ -7,8 +7,8 @@ import re
 
 from google.appengine.api import users
 
-from common.findit_testcase import FinditTestCase
 from libs.http import retry_http_client
+from libs.testcase import TestCase
 from lib.gitiles.change_log import ChangeLog
 from model.crash.crash_config import CrashConfig
 
@@ -82,22 +82,8 @@ DUMMY_CHANGELOG = ChangeLog.FromDict({
 })
 
 
-class MockHttpClient(retry_http_client.RetryHttpClient):  # pragma: no cover.
 
-  def __init__(self):
-    super(MockHttpClient, self).__init__()
-
-  def _Get(self, url, *_):
-    pass
-
-  def _Post(self, *_):
-    pass
-
-  def _Put(self, *_):
-    pass
-
-
-class CrashTestCase(FinditTestCase):  # pragma: no cover.
+class CrashTestCase(TestCase):  # pragma: no cover.
 
   def setUp(self):
     super(CrashTestCase, self).setUp()
@@ -106,6 +92,3 @@ class CrashTestCase(FinditTestCase):  # pragma: no cover.
 
   def GetDummyChangeLog(self):
     return DUMMY_CHANGELOG
-
-  def GetMockHttpClient(self):
-    return MockHttpClient()