PRESUBMIT: Enforce tracker prefix for all BUG entries

PRESUBMIT_test.py

+import unittest
+
+import PRESUBMIT
+from PRESUBMIT_test_mocks import MockInputApi, MockOutputApi
+
+
+class CheckBugEntryField(unittest.TestCase):
+  def testCommitMessageBugEntryWithNoError(self):

[ehmaldonado_webrtc, 2017/09/06 18:50:55]

Check that BUG=None works

[kjellander_webrtc, 2017/09/07 08:28:15]

Thanks for remembering this. It would be annoying if we started failing on that
since it still happens every now and then.

+    mock_input_api = MockInputApi()
+    mock_output_api = MockOutputApi()
+    mock_input_api.change.BUG = 'webrtc:1234'
+    errors = PRESUBMIT._CheckCommitMessageBugEntry(mock_input_api,
+                                                   mock_output_api)
+    self.assertEqual(0, len(errors))
+
+  def testCommitMessageBugEntryReturnError(self):
+    mock_input_api = MockInputApi()
+    mock_output_api = MockOutputApi()
+    mock_input_api.change.BUG = 'webrtc:1234,webrtc=4321'
+    errors = PRESUBMIT._CheckCommitMessageBugEntry(mock_input_api,
+                                                   mock_output_api)
+    self.assertEqual(1, len(errors))
+    self.assertEqual(('Bogus BUG entry: webrtc=4321. Please specify'
+                      ' the issue tracker prefix and the issue number,'
+                      ' separated by a colon, e.g. webrtc:123 or'
+                      ' chromium:12345.'), str(errors[0]))
+

[kjellander_webrtc, 2017/09/06 18:42:08]

nit: +1 blank line

+if __name__ == '__main__':
+    unittest.main()