Re: [PATCH v2 03/21] t/test-lib-functions.sh: generalize test_cmp_rev

> Stephan Beyer <s-beyer@gmx.net> writes:
> 
>> test_cmp_rev() took exactly two parameters, the expected revision
>> and the revision to test. This commit generalizes this function
>> such that it takes any number of at least two revisions: the
>> expected one and a list of actual ones. The function returns true
>> if and only if at least one actual revision coincides with the
>> expected revision.
> 
> There may be cases where you want to find the expected one among
> various things you actually have (which is what the above talks
> about; it is like "list-what-I-actually-got | grep what-i-want"),
> but an equally useful use case would be "I would get only one
> outcome from test, I anticipate one of these things, all of which is
> OK, but I cannot dictate which one of them should come out" (it is
> like "list-what-I-can-accept | grep what-I-actually-got").

> I am not enthused by the new test that implements the "match one
> against multi" check only in one way among these possible two to
> squat on a very generic name, test_cmp_rev.
> 
> The above _may_ appear a non-issue until you realize one thing that
> is there to help those who debug the tests, which is ...
> 
>> While at it, the side effect of generating two (temporary) files
>> is removed.
> 
> That is not strictly a side effect.  test_cmp allows you to see what
> was expected and what you actually had when the test failed (we
> always compare expect with actual and not the other way around, so
> that "diff -u expect actual" would show how the actual behaviour
> diverted from our expectation in a natural way).

> Something with the semantics of these two:
> 
> 	test_revs_have_expected () {
>         	expect=$1
> 		shift
> 		git rev-parse "$@" | grep -e "$expect" >/dev/null && return
> 		echo >&2 "The expected '$1' is not found in:"
>                 printf >&2 " '%s'\n", "$@"
>                 return 1
> 	}
> 
> 	test_rev_among_expected () {
> 		actual=$1
>                 shift
> 		git rev-parse "$@" | grep -e "$actual" >/dev/null && return
> 		echo >&2 "'$1' is not among expected ones:"
>                 printf >&2 " '%s'\n", "$@"
>                 return 1
> 	}
> 
> might be more appropriate.