Hi all, while using `unittest` I see the pattern of creating an error message with the test context for the case that some `assert...` methods fails (to get a good error message). On the lines: class Test...(unittest.TestCase): longMessage = True def test_(self): ... for a, b, c ... in zip(A, B, C, ..): * call the function under test and get the result msg = "Some headline: {}{} ...".format(a, b, c,..) self.assert...( ,msg) The `msg` is just used in case the assert fails but its creation takes time and adds up. What is the best practice/pattern you use here? Or, are there ideas to have a lazy mechanism to avoid that creation and just infer them in the case the assert failed? Thanks in advance! --francis