gistfile1.py

# Watch the file given at the command line 
if __name__ == '__main__':
    old_mtime = 0
    while True:
        if len(sys.argv) == 1:
            print 'Usage: python this_file.py your_module.py'
            sys.exit()
        else:
            test = sys.argv[1].split('.')[0]
            # Load here so we can use imp.reload later
            test_mod = __import__(test)
            # TODO: update this to handle Win
            mtime = os.stat(sys.argv[1]).st_mtime
            if mtime != old_mtime:
                try:
                    old_mtime = mtime
                    # unittest loads as module is already loaded
                    # so needs to be manually reloaded each time
                    imp.reload(test_mod)
                    suite = unittest.TestSuite()
                    suite.addTests(unittest.TestLoader().loadTestsFromName(test))
                    unittest.TextTestRunner().run(suite)
                # Show any exceptions
                except Exception as e:
                    print str(type(e)), e
            time.sleep(1)