Canonical test_XXX.py - nope (was:Re: [Python-Dev] Re: Call for reviewer!) (original) (raw)

Tim Peters tim_one@email.msn.com
Sun, 20 Aug 2000 13:46:35 -0400

[David Goodger]

Glad to contribute. You'll find a regression test module for the current getopt.py as revised patch #101110. I based it on some existing Lib/test/ modules, but haven't found the canonical example or instruction set. Is there one?

[Trent Mick]

I don't really think there is. Kind of folk lore. There are some good examples to follow in the existing test suite. Skip Montanaro wrote a README for writing tests and using the test suite (.../dist/src/Lib/test/README).

Really, the testing framework is extremely simple. Which is one of its benefits. There is not a whole lot of depth that one has not grokked just by writing one testXXX.py.

What he said. The README explains it well, and I think the only thing you (David) missed in your patch was the need to generate the "expected output" file via running regrtest once with -g on the new test case.

I'd add one thing: people use "assert" way too much in the test suite. It's usually much better to just print what you got, and rely on regrtest's output-comparison to complain if what you get isn't what you expected. The primary reason for this is that asserts "vanish" when Python is run using -O, so running regrtest in -O mode simply doesn't test anything caught by an assert.

A compromise is to do both:

print what_i_expected, what_i_got
assert what_i_expected == what_i_got

In Python 3000, I expect we'll introduce a new binary infix operator

!!!

so that

print x !!! y

both prints x and y and asserts that they're equal .