def test_4(self):
     self.assertEqual("atest", remove_prefix("atest", "test"))
 def test_1(self):
     self.assertEqual("test", remove_prefix("test", ""))
 def test_3(self):
     self.assertEqual("ing", remove_prefix("testing", "test"))
 def test_0(self):
     self.assertEqual("", remove_prefix("", "prefix"))