Rewrite thread_watcher_test.

testing_support/tests/thread_watcher_test.py

Index: testing_support/tests/thread_watcher_test.py
diff --git a/testing_support/tests/thread_watcher_test.py b/testing_support/tests/thread_watcher_test.py
index 7bf5aa62a9afd99ff15b54ad55a05f8fccd83334..4989f2d8311a5625b9b4c84ef36e9bff95057875 100644
--- a/testing_support/tests/thread_watcher_test.py
+++ b/testing_support/tests/thread_watcher_test.py
@@ -2,83 +2,111 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import mock
 import re
+import sys
 import threading
-import time
 import unittest
 
 from testing_support import thread_watcher
 
-class TestNoExtraThreads(thread_watcher.TestCase):
-  def mock_test(self):
-    pass
-
-
-class TestExtraThreads(thread_watcher.TestCase):
-  def _start_thread(self, name='foo'):
-    stop = threading.Event()
-    def thread_func():
-      while not stop.is_set():
-        time.sleep(0.01)
 
-    t = threading.Thread(target=thread_func, name=name)
-    t.start()
-    return t, stop
+class _PuppetThread(threading.Thread):
+  def __init__(self, name):
+    super(_PuppetThread, self).__init__(name=name)
+    self.daemon = True
+    self._start_event = threading.Event()
+    self._stop_event = threading.Event()
+    self.start()
+    # For the thread to actually start.
+    self._start_event.wait()
 
-  def mock_test(self):
-    self.t1, self.stop1 = self._start_thread('foo')
-    self.t2, self.stop2 = self._start_thread('bar')
+  def run(self):
+    self._start_event.set()
+    self._stop_event.wait()
 
-  def stopThreads(self):
-    self.stop1.set()
-    self.stop2.set()
-    self.t1.join()
-    self.t2.join()
+  def stop(self):
+    self._stop_event.set()
+    self.join()
 
 
 class ThreadWatcherTestCase(thread_watcher.TestCase):
-  @mock.patch('unittest.TestCase.fail')
-  def test_no_extra_threads(self, fail_mock):
-    TestNoExtraThreads('mock_test').run()
-    self.assertFalse(fail_mock.called)
-
-  @mock.patch('unittest.TestCase.fail')
-  def test_extra_threads(self, fail_mock):
-    t = TestExtraThreads('mock_test')
-    t.run()
-    t.stopThreads()
-
-    self.assertEqual(len(fail_mock.call_args_list), 1)
-    self.assertEqual(len(fail_mock.call_args_list[0]), 2)
-    self.assertEqual(len(fail_mock.call_args_list[0][0]), 1)
-    self.assertEqual(len(fail_mock.call_args_list[0][1]), 0)
-
-    error_message = fail_mock.call_args_list[0][0][0]
+  def setUp(self):
+    self._fail_called = []
+    self.watcher = thread_watcher.ThreadWatcherMixIn()
+    self.watcher.fail = lambda x: self._fail_called.append(x)
+    self._threads = []
+
+  def tearDown(self):
+    for t in self._threads:
+      t.stop()
+
+  def test_no_extra_threads(self):
+    self.watcher.setUp()
+    self.watcher.tearDown()
+    self.assertEqual(self._fail_called, [])
+
+  def test_no_extra_threads_start_stop(self):
+    self.watcher.setUp()
+    self._threads.append(_PuppetThread('puppet1'))
+    self._threads[-1].stop()
+    self.watcher.tearDown()
+    self.assertEqual(self._fail_called, [])
+
+  def test_extra_threads(self):
+    self.watcher.setUp()
+    self._threads.append(_PuppetThread('foo'))
+    self._threads.append(_PuppetThread('bar'))
+    self.watcher.tearDown()
+    self.assertEqual(len(self._fail_called), 1)
+    error_message = self._fail_called[0]
     self.assertRegexpMatches(
         error_message,
-        re.compile('^Found 2 running thread\(s\) after the test.\n\n'
-                   'Thread <Thread\(foo, started \d+\)> stacktrace:\n'
-                   '  .*\n\n'
-                   'Thread <Thread\(bar, started \d+\)> stacktrace:\n'
-                   '  .*\n$', re.DOTALL)
+        re.compile(
+            '^Found 2 running thread\(s\) after the test.\n\n'
+            'Thread <_PuppetThread\(foo, started daemon \d+\)> stacktrace:\n'
+            '  .*\n\n'
+            'Thread <_PuppetThread\(bar, started daemon \d+\)> stacktrace:\n'
+            '  .*\n$', re.DOTALL)
     )
-    self.assertNotIn('  Thread stopped while acquiring stacktrace.\n', error_message)
+    self.assertNotIn('  Thread stopped while acquiring stacktrace.\n',
+                     error_message)
+
+  def test_fail_get_stacktrace(self):
+    self.watcher.setUp()
+    self._threads.append(_PuppetThread('foo'))
+    try:
+      old = sys._current_frames
+      sys._current_frames = lambda: {}
+      self.watcher.tearDown()
+    finally:
+      sys._current_frames = old
+
+    self.assertEqual(len(self._fail_called), 1)
+    error_message = self._fail_called[0]
+    self.assertIn('  Thread stopped while acquiring stacktrace.\n', error_message)
 
-  @mock.patch('unittest.TestCase.fail')
-  def test_fail_get_stacktrace(self, fail_mock):
-    with mock.patch('sys._current_frames', mock.Mock(return_value={})):
-      t = TestExtraThreads('mock_test')
-      t.run()
-      t.stopThreads()
 
-    self.assertEqual(len(fail_mock.call_args_list), 1)
-    self.assertEqual(len(fail_mock.call_args_list[0]), 2)
-    self.assertEqual(len(fail_mock.call_args_list[0][0]), 1)
-    self.assertEqual(len(fail_mock.call_args_list[0][1]), 0)
+class ThreadWatcherTestCaseUsageTest(thread_watcher.TestCase):

[tandrii(chromium), 2016/07/07 11:33:57]

testing actual usage turned out to be very simple

[Sergiy Byelozyorov, 2016/07/08 08:22:13]

Awesome. Thanks.

+  @classmethod
+  def setUpClass(cls):
+    cls._threads = []
+
+  @classmethod
+  def tearDownClass(cls):
+    for t in cls._threads:
+      t.stop()
+
+  @unittest.expectedFailure
+  def test_fail_extra_threads(self):
+    self._threads.append(_PuppetThread(name))
+
+  def test_ok(self):
+    pass
+
+  def test_ok_with_threads(self):
+    self._threads.append(_PuppetThread('ok'))
+    self._threads[-1].stop()
 
-    error_message = fail_mock.call_args_list[0][0][0]
-    self.assertIn('  Thread stopped while acquiring stacktrace.\n', error_message)
 
 
 if __name__ == '__main__':