Re: [PATCH 3/6] t5516 (fetch-push): introduce mk_test_with_name()

From: Jeff King <peff@peff.net>
Date: Mar 20, 2013, 18:58 UTC
Message-ID: <20130320185844.GB30165@sigill.intra.peff.net>
In-Reply-To: <20130320184157.GO3655@google.com>

On Wed, Mar 20, 2013 at 11:41:57AM -0700, Jonathan Nieder wrote:

Show 11 quoted lines

> Ramkumar Ramachandra wrote:
> > Jonathan Nieder wrote:
> 
> >> I dunno.  The helper functions at the top of this test are already
> >> intimidating, so I guess I am looking for a way to avoid making that
> >> problem worse.
> [...]
> > My patch does not make the situation worse in any way:
> 
> Um, yes it does.  It adds another function to learn to an already
> intimidating list.

Personally I do not find the set of helper functions intimidating. I tend to read the tests in a top-down manner: a test is interesting (usually because it fails), and then I want to see what it is doing, so I look at any functions it calls, and so forth.

What I usually find _much_ harder to debug is when there is hidden state leftover from other tests. So even though it is longer to write, I would much rather see:

  test_expect_success 'check that frob only affects foo' '
          set_state_of foo &&
          set_state_of bar &&
          git frob &&
          check_state_of foo &&
          check_state_of bar
  '

than for the test to assume the state of "foo" or "bar" prior to the test. And I think helper functions can help make writing those sorts of pre-conditions more reasonable (and without looking too hard, I think t5516 does an OK job of that).

Related to that is when the helper functions operate on hidden state. In this instance, we have tests that do things like:

    mk_empty &&
    git push testrepo refs/heads/master:refs/remotes/origin/master

and as a reader I say "wait, what's in testrepo?". I can follow mk_empty and see that it hardcodes testrepo, but it is even better if the function and its arguments are named in a way that I don't have to. So even though it is more typing, I would argue that:

  mk_empty testrepo &&
  git push testrepo ...

is better, because the test script is more readable as a unit.

None of this is that huge a deal to me (and yet I seem to have written a page about it :) ), but I figure while we are bikeshedding about test style...

-Peff