Subject: Re: [PATCH] tests: add a special setup where rebase.useBuiltin is off (Re: Git Test Coverage Report (v2.20.0-rc0))

From: Jonathan Nieder <[email-masked]>
Date: Mon, 19 Nov 2018 10:51:09 -0800

Ævar Arnfjörð Bjarmason wrote:
> On Mon, Nov 19 2018, Derrick Stolee wrote:

>> [...]
>> builtin/rebase.c
>> 62c23938fa 55) return env;
>> [...]
>> Ævar Arnfjörð Bjarmason 62c23938f: tests: add a special setup
>> where rebase.useBuiltin is off
>
> This one would be covered with
> GIT_TEST_REBASE_USE_BUILTIN=false. Obviously trivial, but I wonder if
> the rest of the coverage would look different when passed through the various GIT_TEST_* options.

I wonder if we can do better for this kind of thing.

When I do routine development, I am not running tests with any
non-default flags.  So why should tests run with non-default flags
count toward coverage?  Is there a way to make the default test
settings dip their feet into some non-default configurations, without
running the full battery of tests and slowing tests down accordingly?
E.g. is there some kind of smoke test that rebase with
useBuiltin=false works at all that could run, even if I am not running
the full battery of rebase tests?

That's a bit of a non sequitor for this example, which is actual code
to handle GIT_TEST_REBASE_USE_BUILTIN, though.  For it, I wonder why
we need rebase.c to understand the envvar --- couldn't test-lib.sh
take care of setting rebase.useBuiltin to false when it's set?

Thanks,
Jonathan