From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, "David Turner" <novalis@novalis.org>,
"Elijah Newren" <newren@gmail.com>,
"Matheus Tavares" <matheus.bernardino@usp.br>,
"Jeff King" <peff@peff.net>,
"Derrick Stolee" <derrickstolee@github.com>,
"Đoàn Trần Công Danh" <congdanhqx@gmail.com>
Subject: Re: test-lib.sh musings: test_expect_failure considered harmful
Date: Wed, 13 Oct 2021 12:10:43 +0200 [thread overview]
Message-ID: <87o87ti5n6.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <xmqq4k9m6vkw.fsf@gitster.g>
On Tue, Oct 12 2021, Junio C Hamano wrote:
> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>
>> On Mon, Oct 11 2021, Junio C Hamano wrote:
> [...]
>> Presumably with test_expect_failure.
>>
>> I'll change it, in this case we'd end up with a test_expect_success at
>> the end, so it doesn't matter much & I don't care.
>
> I do agree with you that compared to expect_success, which requires
> _all_ steps to succeed, so an failure in any of its steps is
> immediately noticeable, it is harder to write and keep
> expect_failure useful, because it is not like we are happy to see
> any failure in any step. We do not expect a failure in many
> preparation and conclusion steps in the &&-chain in expect_failure
> block, and we consider it is an error if these steps fail. We only
> want to mark only a single step to exhibit an expected but undesirable
> behaviour.
>
> But even with the shortcomings of expect_failure, it still is much
> better than claiming that we expect a bogus outcome.
>
> Improving the shortcomings of expect_failure would be a much better
> use of our time than advocating an abuse of expect_sucess, I would
> think.
I'd like to improve it, but I'll have to get any patch in this are past
you :)
My reading of your opinion from past exchanges is that you find it
objectionable to say "this is a success" when it's not the /desired/
behavior, whereas I think it's valuable to just test for and document
the exact existing behavior, even if it's not desirable. So you don't
really need a function different from test_expect_success, just a
comment saying "this should change", or add a ("non-hash so it's not TAP
syntax") "TODO" to the description of the test.
But if you agree that we shouldn't conflate failures in the different
steps I think we're getting somewhere, so to begin with what do you
think about the hack in the v2 of my series?
https://lore.kernel.org/git/cover-v2-0.2-00000000000-20211012T142950Z-avarab@gmail.com/
If we were to prompote those semantics to something that
test_expect_failure would use it would be the below, which I think is
the only sensible way to use it.
But that would mean changing all existing test_expect_failure uses in
the test suite, so it would need either a pretty large patch, or some
incremental steps to get there:
But it will mean we can't use it for any test that's actually flaky, so
we'll need a test_expect_flaky, or have some test-specific workarounds
in those areas.
diff --git a/t/t7815-grep-binary.sh b/t/t7815-grep-binary.sh
index 90ebb64f46e..9a95c9e7d69 100755
--- a/t/t7815-grep-binary.sh
+++ b/t/t7815-grep-binary.sh
@@ -64,7 +64,7 @@ test_expect_success 'git grep ile a' '
'
test_expect_failure 'git grep .fi a' '
- git grep .fi a
+ test_must_fail git grep .fi a
'
test_expect_success 'grep respects binary diff attribute' '
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 8361b5c1c57..6d9291b7ead 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -728,8 +728,8 @@ test_known_broken_ok_ () {
then
write_junit_xml_testcase "$* (breakage fixed)"
fi
- test_fixed=$(($test_fixed+1))
- say_color error "ok $test_count - $@ # TODO known breakage vanished"
+ test_broken=$(($test_broken+1))
+ say_color warn "not ok $test_count - $@ # TODO known breakage"
}
test_known_broken_failure_ () {
@@ -737,8 +737,8 @@ test_known_broken_failure_ () {
then
write_junit_xml_testcase "$* (known breakage)"
fi
- test_broken=$(($test_broken+1))
- say_color warn "not ok $test_count - $@ # TODO known breakage"
+ test_fixed=$(($test_fixed+1))
+ say_color error "not ok $test_count - $@ # TODO a 'known breakage' changed behavior!"
}
test_debug () {
next prev parent reply other threads:[~2021-10-13 10:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 9:23 test-lib.sh musings: test_expect_failure considered harmful Ævar Arnfjörð Bjarmason
2021-10-12 16:45 ` Junio C Hamano
2021-10-13 10:10 ` Ævar Arnfjörð Bjarmason [this message]
2021-10-13 13:05 ` Derrick Stolee
2021-10-13 17:16 ` Junio C Hamano
2021-10-14 17:11 ` Ævar Arnfjörð Bjarmason
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