Added unittests for run_slave

slave/tests/run_slave_test.py

Index: slave/tests/run_slave_test.py
diff --git a/slave/tests/run_slave_test.py b/slave/tests/run_slave_test.py
new file mode 100755
index 0000000000000000000000000000000000000000..8cf96997568eda234ed0713b78788ea0a8a500bc
--- /dev/null
+++ b/slave/tests/run_slave_test.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+# Copyright 2016 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.
+
+"""Starts run_slave and verify if it starts successfully.
+"""
+
+import mock
+import os
+import re
+import runpy
+import subprocess
+import sys
+import unittest
+
+
+RUN_SLAVE_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..")
+sys.path.append(RUN_SLAVE_PATH)
+
+import run_slave
+
+# import twisted to mock run()
+_, tw_ver = run_slave.GetThirdPartyVersions(None)
+sys.path.append(os.path.join(RUN_SLAVE_PATH, 'third_party', tw_ver))
+import twisted.scripts.twistd
+
+
+class ExecvExecuted(Exception):
+  # This exception is raised within a mocked os.execv() so that
+  # the execution flow gets interrupted.
+  pass
+
+
+def _GetCallArgumentFromMock(mock_call, position, keyword=None):
+  args, kwargs = mock_call.call_args
+  return kwargs[keyword] if keyword and keyword in kwargs else args[position]
+
+
+class RunSlaveTest(unittest.TestCase):
+  @mock.patch('subprocess.call')
+  @mock.patch('os.execv', mock.Mock(side_effect=ExecvExecuted))
+  def test_run_slave_restart_after_gclient_sync(self, subprocess_call):
+    """Tests if run_slave restarts itself after gclient sync."""
+    with self.assertRaises(ExecvExecuted):
+      runpy.run_module("run_slave", run_name="__main__", alter_sys=True)
+
+    # verify that gclient sync has been executed
+    self.assertTrue(subprocess_call.called)
+    call_cmd_args = _GetCallArgumentFromMock(subprocess_call, 0, 'args')
+    self.assertEqual(call_cmd_args[0], run_slave.GetGClientPath())
+    self.assertEqual(call_cmd_args[1], 'sync')
+
+    # verify that run_slave.py was execv()-ed with --no-gclient-sync
+    run_slave_py_path = re.sub(
+        r'pyc$', 'py', os.path.abspath(run_slave.__file__))
+
+    execv_cmd_args = _GetCallArgumentFromMock(os.execv, 1, 'args')
+    self.assertIn(run_slave_py_path, execv_cmd_args[:2])
+    self.assertIn('--no-gclient-sync', execv_cmd_args[1:])
+
+  @mock.patch('subprocess.call')
+  @mock.patch('subprocess.check_call')
+  @mock.patch('subprocess.check_output')
+  @mock.patch('twisted.scripts.twistd.run')
+  @mock.patch('sys.argv', [run_slave.__file__, '--no-gclient-sync'])
+  def test_run_slave_with_no_gclient_sync(self, twistd_run,
+                                          subprocess_check_output,
+                                          subprocess_check_call,
+                                          subprocess_call):
+    """Tests if twistd.run() gets invoked when --no-gclient-sync is given."""
+    os.environ['TESTING_MASTER'] = 'Master1'
+    os.environ['TESTING_SLAVE'] = 'Slave1'
+    runpy.run_module("run_slave", run_name="__main__", alter_sys=True)
+
+    gclient_path = run_slave.GetGClientPath()
+    for mock_call in (subprocess_call, subprocess_check_call,
+                      subprocess_check_output):
+      if mock_call.called:
+        cmd_args = _GetCallArgumentFromMock(mock_call, 0, 'args')
+
+        # verify that gclient with sync option has not been called within
+        # run_slave.
+        if gclient_path == cmd_args[0]:
+          self.assertNotEqual(cmd_args[1], 'sync')
+
+    self.assertTrue(twistd_run.called)
+
+
+if __name__ == '__main__':
+  unittest.main()