Added non-zero exit code for errors/failures during tests.

runner.py

@@ -145,4 +145,9 @@ def main(tests, verbose=0, color=True):
     runner = TextTestRunner(verbosity=verbose, color=color)
     suite = unittest.TestSuite(testcases)
     suite.filename = testfile
-    runner.run(suite)
+
+    result = runner.run(suite)
+
+    # Return non zero exit code if there are failures or errors occured.
+    if result.failures or result.errors:
+        sys.exit(1)