[Python-ideas] Add links in manual to test_modules.

Guido van Rossum guido at python.org
Sat Mar 19 17:22:50 CET 2011

On Fri, Mar 18, 2011 at 11:45 PM, Steven D'Aprano <steve at pearwood.info> wrote:
> Nick Coghlan wrote:
>> Ick, no.
>> We do all sorts of dodgy stuff in our test suite to stress
>> implementations, probe obscure corner cases, double up on checks based
>> on where and when bugs happened to be reported. Large parts of it are
>> written to make the tests easier to write, not because they reflect
>> any kind of idiomatic code, or good ways of doing things in a real
>> application.
> But surely a test suite counts as a real application? It's likely to be
> bigger than the "actual" application or library, it still needs to be
> maintained, and is more likely to have bugs (on account of there being no
> test suite for the tests).
> Speaking for myself, I find code reuse and design of my test suites to be
> one of the harder parts of writing code. Perhaps I'd learn something from
> the Python tests, even if only "everyone has trouble writing good
> unit-tests" *wink*
> As I see it, the main benefit of Terry's suggestion is that it may encourage
> developers to write new tests for the standard library, or to refactor the
> existing tests. +0.5 from me.

I'm with Nick. Tests (at least the ones we have for the standard
library) are rarely any good as example code for the modules being
tested. They may be great if you want to learn to write tests or if
you want to contribute to the stdlib, but they are easy enough to
find. Linking them from the docs is sending people to a body of code
that most people should never peruse.

The one exception is that the tests can show language/library lawyers
how something is supposed to behave in more detail than docs, without
having to actually read the source. But again that's pretty advanced
and the people interested in that stuff know where to go.

--Guido van Rossum (python.org/~guido)

More information about the Python-ideas mailing list