mojo: Add async waiter for python bindings

mojo/python/tests/async_wait_unittest.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.
+
+import unittest
+
+# pylint: disable=F0401
+import mojo.embedder
+from mojo import system
+
+
+class AsyncWaitTest(unittest.TestCase):
+
+  def setUp(self):
+    mojo.embedder.Init()
+    self.loop = system.RunLoop()
+    self.array = []
+    self.handles = system.MessagePipe()
+    self.cancel = self.handles.handle0.AsyncWait(system.HANDLE_SIGNAL_READABLE,
+                                                 system.DEADLINE_INDEFINITE,
+                                                 self.OnResult)
+    self.loop.PostDelayedTask(self.WriteToHandle, 100)
+
+  def tearDown(self):
+    self.handles = None
+    self.array = None
+    self.loop = None
+
+  def OnResult(self, value):
+    self.array.append(value)
+
+  def WriteToHandle(self):
+    self.handles.handle1.WriteMessage()
+
+  def testAsyncWait(self):
+    self.loop.RunUntilIdle()
+    self.assertEquals(len(self.array), 1)
+    self.assertEquals(system.RESULT_OK, self.array[0])
+    self.cancel()
+
+  def testAsyncWaitCancel(self):
+    self.loop.PostDelayedTask(self.cancel, 50)
+    self.loop.RunUntilIdle()
+    self.assertEquals(len(self.array), 0)
+    self.cancel()
+
+  def testAsyncWaitImmediateCancel(self):
+    self.cancel()
+    self.loop.RunUntilIdle()
+    self.assertEquals(len(self.array), 0)
+    self.cancel()