From: Andrei Rybak <rybak.a.v@gmail.com>
To: Jeff King <peff@peff.net>
Cc: "Junio C Hamano" <gitster@pobox.com>,
"SZEDER Gábor" <szeder.dev@gmail.com>,
"Git mailing list" <git@vger.kernel.org>,
"Kirill Smelkov" <kirr@nexedi.com>
Subject: Re: [PATCH] t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test
Date: Sun, 19 Aug 2018 23:37:59 +0200 [thread overview]
Message-ID: <aedb7f33-65cc-5d63-4e7e-dd5f37831e19@gmail.com> (raw)
In-Reply-To: <20180819203253.GA5789@sigill.intra.peff.net>
On 19/08/18 22:32, Jeff King wrote:
> On Sun, Aug 19, 2018 at 07:50:42PM +0200, Andrei Rybak wrote:
>
>> 1. Check both files at the same time (combination with Gábor's
>> function):
>>
>> test_cmp () {
>> if test "$1" != - &&
>> test "$2" != - &&
>> ! test -s "$1" &&
>> ! test -s "$2"
>> then
>> error "bug in test script: using test_cmp to check empty file; use test_must_be_empty instead"
>> fi
>> test_cmp_allow_empty "$@"
>> }
>>
>> This will still be reporting to the developer clearly, but
>> will only catch cases exactly like the bogus test in t5310.
>
> Doesn't that have the opposite issue? If we expect non-empty output but
> the command produces empty output, we'd say "bug in the test script".
> But that is not true at all; it's a failed test.
No. Only when both "$1" and "$2" are empty files will the function above
report "bug in test script". From patch's commit message:
... both invocations produce empty 'pack{a,b}.objects' files, and the
subsequent 'test_cmp' happily finds those two empty files identical.
That's what I meant by "will only catch cases exactly like the bogus
test in t5310".
However ...
> If we assume that "expect" is first (which is our convention but not
> necessarily guaranteed), then I think the best logic is something like:
>
> if $1 is empty; then
> bug in the test script
> elif test_cmp_allow_empty "$@"
> test failure
>
> We do not need to check $2 at all. An empty one is either irrelevant (if
> the expectation is empty), or a test failure (because it would not match
> the non-empty $1).
... this is indeed a better solution. I written out the cases for
updated test_cmp to straighten out my thinking:
* both $1 and $2 are empty:
bogus test:
needs either fixing generation of both expect and actual
or switching to test_must_be_empty
OR
bogus helper function, as Gábor described above:
needs to switch to test_cmp_allow_empty
* $1 is non-empty && $2 is empty
proceeding with test
test failure from GIT_TEST_CMP
* $1 is empty && $2 is non-empty
bogus test - needs either switching to test_must_be_empty
(and after that test_must_be_empty will report failure)
or fixing generation of expect (and after that test result
depends on contents).
* both $1 and $2 are non-empty
proceeding with test
result depends on contents
next prev parent reply other threads:[~2018-08-19 21:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-14 11:47 [PATCH] t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test SZEDER Gábor
2018-08-14 21:49 ` Jeff King
2018-08-16 20:51 ` Andrei Rybak
2018-08-16 22:36 ` Junio C Hamano
2018-08-17 17:39 ` SZEDER Gábor
2018-08-17 19:27 ` Andrei Rybak
2018-08-17 20:09 ` Junio C Hamano
2018-08-19 17:50 ` Andrei Rybak
2018-08-19 20:32 ` Jeff King
2018-08-19 21:37 ` Andrei Rybak [this message]
2018-08-19 21:43 ` Jeff King
2018-08-21 21:52 ` Junio C Hamano
2018-08-17 20:15 ` SZEDER Gábor
2018-08-22 18:14 ` Matthew DeVore
2018-08-27 10:22 ` Kirill Smelkov
2018-08-27 23:04 ` Jeff King
2018-08-28 6:37 ` Kirill Smelkov
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