mojo: Add RunLoop::Current() and refactor unit tests.

mojo/python/tests/mojo_unittest.py

Index: mojo/python/tests/mojo_unittest.py
diff --git a/mojo/python/tests/mojo_unittest.py b/mojo/python/tests/mojo_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..144342b3f7f8c3f22b3c78dd7f3accdce7dabfb7
--- /dev/null
+++ b/mojo/python/tests/mojo_unittest.py
@@ -0,0 +1,19 @@
+# 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
+import mojo.system as system
+
+
+class MojoTestCase(unittest.TestCase):
+
+  def setUp(self):
+    mojo.embedder.Init()
+    self.loop = system.RunLoop()
+
+  def tearDown(self):
+    self.loop = None