Re: [RFC PATCH 0/2] add an external testing library for unit tests

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 27, 2023, 18:39 UTC
Message-ID: <xmqqr0s5jhj4.fsf@gitster.g>
In-Reply-To: <20230427175007.902278-1-calvinwan@google.com>

Calvin Wan <calvinwan@google.com> writes:

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> ... Unit tests additionally provide stability to the
> codebase and can simplify debugging through isolation. Turning parts of
> Git into libraries[1] gives us the ability to run unit tests on the
> libraries and to write unit tests in C. Writing unit tests in pure C,
> rather than with our current shell/test-tool helper setup, simplifies
> test setup, simplifies passing data around (no shell-isms required), and
> reduces testing runtime by not spawning a separate process for every
> test invocation.

Good goal, except that unit tests are not panacea---our ultimate obligation is to give a stable behaviour to the end users and end-to-end testing is still needed. We would benefit from having tests at both levels.

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> Unit testing in C requires a separate testing harness that we ideally
> would like to be TAP-style and to come with a non-restrictive license.
>
> Fortunately, there already exists a C TAP harness library[2] with an MIT
> license (at least for the files included in this series).

Yup. Consistency with our existing test framework would make it easier to adopt for all of us. Good goal.