threads / patch / 50899

patchFix a false negative in t3301-notes.sh

Subject: [PATCH 0/1] Fix a false negative in t3301-notes.sh

## tl;dr

3 messages between Apr 9, 2019 and Apr 9, 2019. Diffs are folded; open one to read it.

replies: 2people: 2as markdown or json

Johannes Schindelin via GitGitGadget· Apr 9, 2019, 10:41 UTC · lore

It is always bad when test cases fail for the wrong reasons, but it is in some ways more scary when they pass for the wrong reasons.

I stumbled over this issue while chasing down a Windows-specific issue that caused two other test cases to fail, and should have caused this one to fail, too, but didn't.

Johannes Schindelin (1):
  t3301: fix false negative

 t/t3301-notes.sh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

base-commit: 8104ec994ea3849a968b4667d072fedd1e688642
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-176%2Fdscho%2Ffix-false-negative-in-t3301-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-176/dscho/fix-false-negative-in-t3301-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/176

-- 
gitgitgadget

Johannes Schindelin via GitGitGadget· Apr 9, 2019, 10:41 UTC · re: Johannes Schindelin via GitGitGadget · lore

[PATCH 1/1] t3301: fix false negative

From: Johannes Schindelin <johannes.schindelin@gmx.de>

In 6956f858f6 (notes: implement helpers needed for note copying during rewrite, 2010-03-12), we introduced a test case that verifies that the config setting `notes.rewriteRef` can be overridden via the environment variable `GIT_NOTES_REWRITE_REF`.

Back when it was introduced, it relied on a side effect of an earlier test case that configured `core.noteRef` to point to `refs/notes/other`.

In 908a320363 (t3301: modernize style, 2014-11-12), this side effect was removed.

The test case *still* passed, but for the wrong reason: we no longer overrode the rewrite ref, but there simply was nothing to rewrite anymore, as the overridden notes ref was "modernized" away.

Let's let that test case pass for the correct reason again.

To make sure of that, let's change the idea of the original test case: it configured `notes.rewriteRef` to point to the actual notes ref, forced that to be ignored and then verified that the notes were *not* rewritten.

By turning that idea upside down (configure the `notes.rewriteRef` to another notes ref, override it via the environment variable to force the notes to be copied, and then verify that the notes *were* rewritten), we make it much harder for that test case to pass for the wrong reason.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/t3301-notes.sh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Show changes to t/t3301-notes.sh +3 −2

diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
index 84bbf88cf9..704bbc6541 100755
--- a/t/t3301-notes.sh
+++ b/t/t3301-notes.sh
@@ -1120,9 +1120,10 @@ test_expect_success 'GIT_NOTES_REWRITE_REF overrides config' '
 	test_config notes.rewriteMode overwrite &&
 	test_config notes.rewriteRef refs/notes/other &&
 	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
-	GIT_NOTES_REWRITE_REF= git notes copy --for-rewrite=foo &&
+	GIT_NOTES_REWRITE_REF=refs/notes/commits \
+		git notes copy --for-rewrite=foo &&
 	git log -1 >actual &&
-	test_cmp expect actual
+	grep "replacement note 3" actual
 '
 
 test_expect_success 'git notes copy diagnoses too many or too few parameters' '

-- 
gitgitgadget

Junio C Hamano· Apr 9, 2019, 11:33 UTC · re: Johannes Schindelin via GitGitGadget · lore

Re: [PATCH 1/1] t3301: fix false negative

"Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com> writes:

Show 16 quoted lines

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> In 6956f858f6 (notes: implement helpers needed for note copying during
> rewrite, 2010-03-12), we introduced a test case that verifies that the
> config setting `notes.rewriteRef` can be overridden via the environment
> variable `GIT_NOTES_REWRITE_REF`.
>
> Back when it was introduced, it relied on a side effect of an earlier
> test case that configured `core.noteRef` to point to `refs/notes/other`.
>
> In 908a320363 (t3301: modernize style, 2014-11-12), this side effect was
> removed.
>
> The test case *still* passed, but for the wrong reason: we no longer
> overrode the rewrite ref, but there simply was nothing to rewrite
> anymore, as the overridden notes ref was "modernized" away.

Wow.  Thanks for digging thru this

Show 11 quoted lines

> Let's let that test case pass for the correct reason again.
>
> To make sure of that, let's change the idea of the original test case:
> it configured `notes.rewriteRef` to point to the actual notes ref,
> forced that to be ignored and then verified that the notes were *not*
> rewritten.
>
> By turning that idea upside down (configure the `notes.rewriteRef` to
> another notes ref, override it via the environment variable to force the
> notes to be copied, and then verify that the notes *were* rewritten), we
> make it much harder for that test case to pass for the wrong reason.

Yup. I agree that testing positive side, expressing what we want to happen in a more explicit manner, is always a better alternative.

Will queue.  Thanks.

Show 16 quoted lines

> index 84bbf88cf9..704bbc6541 100755
> --- a/t/t3301-notes.sh
> +++ b/t/t3301-notes.sh
> @@ -1120,9 +1120,10 @@ test_expect_success 'GIT_NOTES_REWRITE_REF overrides config' '
>  	test_config notes.rewriteMode overwrite &&
>  	test_config notes.rewriteRef refs/notes/other &&
>  	echo $(git rev-parse HEAD^) $(git rev-parse HEAD) |
> -	GIT_NOTES_REWRITE_REF= git notes copy --for-rewrite=foo &&
> +	GIT_NOTES_REWRITE_REF=refs/notes/commits \
> +		git notes copy --for-rewrite=foo &&
>  	git log -1 >actual &&
> -	test_cmp expect actual
> +	grep "replacement note 3" actual
>  '
>  
>  test_expect_success 'git notes copy diagnoses too many or too few parameters' '