From: Junio C Hamano <gitster@pobox.com>
To: Eric Sunshine <sunshine@sunshineco.com>
Cc: git@vger.kernel.org, Elijah Newren <newren@gmail.com>,
Shourya Shukla <shouryashukla.oo@gmail.com>
Subject: Re: [PATCH v2] test_cmp: diagnose incorrect arguments
Date: Sun, 09 Aug 2020 12:12:37 -0700 [thread overview]
Message-ID: <xmqq7du7eiqi.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <20200809174209.15466-1-sunshine@sunshineco.com> (Eric Sunshine's message of "Sun, 9 Aug 2020 13:42:09 -0400")
Eric Sunshine <sunshine@sunshineco.com> writes:
> Under normal circumstances, if a test author misspells a filename passed
> to test_cmp(), the error is quickly discovered when the test fails
> unexpectedly due to test_cmp() being unable to find the file. However,
> if the test is expected to fail, as with test_expect_failure(), a
> misspelled filename as argument to test_cmp() will go unnoticed since
> the test will indeed fail, but for the wrong reason. Make it easier for
> test authors to discover such problems early by sanity-checking the
> arguments to test_cmp(). To avoid penalizing all clients of test_cmp()
> in the general case, only check for missing files if the comparison
> fails.
>
> While at it, make test_cmp_bin() sanity-check its arguments, as well.
>
> Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
> ---
The motivation makes quite a lot of sense.
I suspect that it is a bug to use "-", i.e. "read from the standard
input", for "$2", because
(1) if it is used for the expected output, we got the comparison in
the wrong direction;
(2) if it is used for the actual output, we have a command whose
output we are interested in on the upstream side of a pipe to
discard its exit status.
but I'll let it pass.
> diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
> index b791933ffd..a12d6a3fc9 100644
> --- a/t/test-lib-functions.sh
> +++ b/t/test-lib-functions.sh
> @@ -952,7 +952,13 @@ test_expect_code () {
> # - not all diff versions understand "-u"
>
> test_cmp() {
> - eval "$GIT_TEST_CMP" '"$@"'
> + test $# -eq 2 || BUG "test_cmp requires two arguments"
> + if ! eval "$GIT_TEST_CMP" '"$@"'
> + then
> + test "x$1" = x- || test -e "$1" || BUG "test_cmp '$1' missing"
> + test "x$2" = x- || test -e "$2" || BUG "test_cmp '$2' missing"
> + return 1
> + fi
> }
>
> # Check that the given config key has the expected value.
> @@ -981,7 +987,13 @@ test_cmp_config() {
> # test_cmp_bin - helper to compare binary files
>
> test_cmp_bin() {
> - cmp "$@"
> + test $# -eq 2 || BUG "test_cmp_bin requires two arguments"
> + if ! cmp "$@"
> + then
> + test "x$1" = x- || test -e "$1" || BUG "test_cmp_bin '$1' missing"
> + test "x$2" = x- || test -e "$2" || BUG "test_cmp_bin '$2' missing"
> + return 1
> + fi
> }
>
> # Use this instead of test_cmp to compare files that contain expected and
next prev parent reply other threads:[~2020-08-09 19:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-09 6:08 [PATCH] test_cmp: diagnose incorrect arguments Eric Sunshine
2020-08-09 8:32 ` Shourya Shukla
2020-08-09 8:49 ` Eric Sunshine
2020-08-09 17:42 ` [PATCH v2] " Eric Sunshine
2020-08-09 19:12 ` Junio C Hamano [this message]
2020-08-09 19:34 ` Eric Sunshine
2020-08-10 15:22 ` Junio C Hamano
2020-08-11 18:32 ` Taylor Blau
2020-08-11 19:25 ` Eric Sunshine
2020-08-11 21:03 ` Taylor Blau
2020-08-12 15:37 ` Jeff King
2020-08-12 16:15 ` Eric Sunshine
2020-08-12 16:39 ` Eric Sunshine
2020-08-12 17:10 ` Jeff King
2020-10-16 0:17 ` Jeff King
2020-10-16 2:18 ` Eric Sunshine
2020-10-16 18:36 ` Junio C Hamano
2020-10-16 20:56 ` Junio C Hamano
2020-10-16 23:14 ` Junio C Hamano
2020-10-17 6:06 ` Eric Sunshine
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