def assert_output(self, stream, msg):
        """
        Utility assertion: assert that the given message exists in the output
        """
        self.failUnless(msg in stream, 
                (msg, stream) % "'%s' does not match actual output text '%s'")
dataset/ETHPy150Open jcbagneris/fms/tests/startfms_tests.py/LauncherTests.assert_output/swapped operands of `%`