From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 16 Nov 2021 06:09:08 GMT
Subject: Re: [PATCH 2/2] test-lib: introduce required prereq for test runs
Message-ID: <xmqqpmr0bpiz.fsf@gitster.g>
In-Reply-To: <20211115160750.1208940-3-fs@gigacodes.de>

Fabian Stelzer <fs@gigacodes.de> writes:

> In certain environments or for specific test scenarios we might expect a
> specific prerequisite check to be succeed. Therefore we would like to

"to be succeed" -> "to succeed"?

> trigger an error when running our tests if this is not the case.
>
> To remedy this we add the environment variable GIT_TEST_REQUIRE_PREREQ
> which can be set to a comma separated list of prereqs. If one of these
> prereq tests fail then the whole test run will abort.
>
> Signed-off-by: Fabian Stelzer <fs@gigacodes.de>
> ---
>  t/README                |  6 ++++++
>  t/test-lib-functions.sh | 11 +++++++++++
>  2 files changed, 17 insertions(+)
>
> diff --git a/t/README b/t/README
> index 29f72354bf..18ce75976e 100644
> --- a/t/README
> +++ b/t/README
> @@ -466,6 +466,12 @@ explicitly providing repositories when accessing submodule objects is
>  complete or needs to be abandoned for whatever reason (in which case the
>  migrated codepaths still retain their performance benefits).
>  
> +GIT_TEST_REQUIRE_PREREQ=<list> allows specifying a comma speparated list of
> +prereqs that are required to succeed. If a prereq in this list is triggered by
> +a test and then fails then the whole test run will abort. This can help to make
> +sure the expected tests are executed and not silently skipped when their
> +dependency breaks or is simply not present in a new environment.
> +
>  Naming Tests
>  ------------
>  
> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
> index eef2262a36..2c8abf3420 100644
> --- a/t/test-lib-functions.sh
> +++ b/t/test-lib-functions.sh
> @@ -680,6 +680,17 @@ test_have_prereq () {
>  			# Keep a list of missing prerequisites; restore
>  			# the negative marker if necessary.
>  			prerequisite=${negative_prereq:+!}$prerequisite
> +
> +			# Abort if this prereq was marked as required
> +			if test -n $GIT_TEST_REQUIRE_PREREQ
> +			then
> +				case ",$GIT_TEST_REQUIRE_PREREQ," in
> +				*,$prerequisite,*)
> +					error "required prereq $prerequisite failed"
> +					;;
> +				esac
> +			fi
> +
>  			if test -z "$missing_prereq"
>  			then
>  				missing_prereq=$prerequisite