On Nov 25, 2017, at 9:16 AM, Ian Kelly <ian.g.ke...@gmail.com> wrote: > >> On Sat, Nov 25, 2017 at 10:02 AM, Chris Angelico <ros...@gmail.com> wrote: >>> On Sun, Nov 26, 2017 at 3:36 AM, Ian Kelly <ian.g.ke...@gmail.com> wrote: >>>> On Sat, Nov 25, 2017 at 6:00 AM, bartc <b...@freeuk.com> wrote: >>>> Where are your unittests for these unittests? >>> >>> No, the point of having unit tests is to build confidence that the >>> code in question works correctly. It's *possible* that the code is >>> broken, and that the test is also broken in a way that hides the >>> brokenness of the code, but this is much less likely than the case >>> where just the code is broken. This is also the reason why the >>> philosophy of test-drive development stipulates that one should write >>> the test *first*, run it and watch it fail (this ensures that the test >>> is actually testing *something*) and then and only then write the code >>> to make the test pass. >> >> To be fair, TDD doesn't actually prove that the test isn't broken. It >> only protects you against one class of error: tests that actually >> aren't testing anything. Proponents of TDD will argue that this class >> of error is quite common; true or not, it's still only one particular >> kind of failure. It's definitely possible for tests to be wrong in >> such a way that they don't detect faulty code. >> >> So what do we do? WE TEST BY HAND. Ultimately, unit testing is a tool, >> not a magic wand. It's up to us to actually put it to use to improve >> code quality. > > Certainly. I wasn't trying to advocate for TDD here, which I don't > even practice regularly myself. > -- > https://mail.python.org/mailman/listinfo/python-list
For anyone who is interested, "Test-Driven Development with Python: Obey the Testing Goat: Using Django, Selenium, and JavaScript" by Harry J.W. Percival. The second edition came out this year. A good introduction to unit and function testing. Chris R. -- https://mail.python.org/mailman/listinfo/python-list
