[v3,2/2] t7063: mtime-mangling instead of delays in untracked cache testing

Commit Message

Tao Klerks March 2, 2022, 6:05 a.m. UTC

From: Tao Klerks <[e-mail]>

The untracked cache test uses an avoid_racy function to deal with
an mtime-resolution challenge in testing: If an untracked cache
entry's mtime falls in the same second as the mtime of the index
the untracked cache was stored in, then it cannot be trusted.

Explicitly delaying tests is a simple effective strategy to
avoid these issues, but should be avoided where possible.

Switch from a delay-based strategy to instead backdating
all file changes using test-tool chmtime, where that is an
option, to shave 9 seconds off the test run time.

Don't update test cases that delay for other reasons, for now at
least (4 seconds).

Signed-off-by: Tao Klerks <[e-mail]>
---
 t/t7063-status-untracked-cache.sh | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

Comments

Johannes Schindelin March 9, 2022, 9:53 p.m. UTC | #1

Hi Tao,

On Wed, 2 Mar 2022, Tao Klerks via GitGitGadget wrote:

> diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
> index a0c123b0a77..ca90ee805e7 100755
> --- a/t/t7063-status-untracked-cache.sh
> +++ b/t/t7063-status-untracked-cache.sh
> @@ -90,6 +90,9 @@ test_expect_success 'setup' '
>  	cd worktree &&
>  	mkdir done dtwo dthree &&
>  	touch one two three done/one dtwo/two dthree/three &&
> +	test-tool chmtime =-300 one two three done/one dtwo/two dthree/three &&
> +	test-tool chmtime =-300 done dtwo dthree &&
> +	test-tool chmtime =-300 . &&

At first I puzzled why we need `done`, `dtwo`, dthree` and `.`, too, but
it makes sense: the invariant is that all of the files/directories whose
mtime is adjusted in these three new lines have the same mtime.

A similar issue is...

> @@ -520,14 +519,14 @@ test_expect_success 'create/modify files, some of which are gitignored' '
>  	echo three >done/three && # three is gitignored
>  	echo four >done/four && # four is gitignored at a higher level
>  	echo five >done/five && # five is not gitignored
> -	echo test >base && #we need to ensure that the root dir is touched
> -	rm base &&
> +	test-tool chmtime =-180 done/two done/three done/four done/five done &&
> +	# we need to ensure that the root dir is touched (in the past);
> +	test-tool chmtime =-180 . &&

Here, where I needed a moment to understand the invariant (and hence the
need to adjust more than just the root directory's mtime).


> @@ -597,11 +595,11 @@ EOF
>  test_expect_success 'set up for test of subdir and sparse checkouts' '
>  	mkdir done/sub &&
>  	mkdir done/sub/sub &&
> -	echo "sub" > done/sub/sub/file
> +	echo "sub" > done/sub/sub/file &&
> +	test-tool chmtime =-120 done/sub/sub/file done/sub/sub done/sub done

Similar situation here, too.

All this is to say that this patch looks good to me.

Thanks,
Dscho

Patch

diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
index a0c123b0a77..ca90ee805e7 100755
--- a/t/t7063-status-untracked-cache.sh
+++ b/t/t7063-status-untracked-cache.sh
@@ -90,6 +90,9 @@  test_expect_success 'setup' '
 	cd worktree &&
 	mkdir done dtwo dthree &&
 	touch one two three done/one dtwo/two dthree/three &&
+	test-tool chmtime =-300 one two three done/one dtwo/two dthree/three &&
+	test-tool chmtime =-300 done dtwo dthree &&
+	test-tool chmtime =-300 . &&
 	git add one two done/one &&
 	: >.git/info/exclude &&
 	git update-index --untracked-cache &&
@@ -142,7 +145,6 @@  two
 EOF
 
 test_expect_success 'status first time (empty cache)' '
-	avoid_racy &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../actual &&
@@ -166,7 +168,6 @@  test_expect_success 'untracked cache after first status' '
 '
 
 test_expect_success 'status second time (fully populated cache)' '
-	avoid_racy &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../actual &&
@@ -190,8 +191,8 @@  test_expect_success 'untracked cache after second status' '
 '
 
 test_expect_success 'modify in root directory, one dir invalidation' '
-	avoid_racy &&
 	: >four &&
+	test-tool chmtime =-240 four &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../actual &&
@@ -241,7 +242,6 @@  EOF
 '
 
 test_expect_success 'new .gitignore invalidates recursively' '
-	avoid_racy &&
 	echo four >.gitignore &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
@@ -292,7 +292,6 @@  EOF
 '
 
 test_expect_success 'new info/exclude invalidates everything' '
-	avoid_racy &&
 	echo three >>.git/info/exclude &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
@@ -520,14 +519,14 @@  test_expect_success 'create/modify files, some of which are gitignored' '
 	echo three >done/three && # three is gitignored
 	echo four >done/four && # four is gitignored at a higher level
 	echo five >done/five && # five is not gitignored
-	echo test >base && #we need to ensure that the root dir is touched
-	rm base &&
+	test-tool chmtime =-180 done/two done/three done/four done/five done &&
+	# we need to ensure that the root dir is touched (in the past);
+	test-tool chmtime =-180 . &&
 	sync_mtime
 '
 
 test_expect_success 'test sparse status with untracked cache' '
 	: >../trace.output &&
-	avoid_racy &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../status.actual &&
 	iuc status --porcelain >../status.iuc &&
@@ -570,7 +569,6 @@  EOF
 '
 
 test_expect_success 'test sparse status again with untracked cache' '
-	avoid_racy &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../status.actual &&
@@ -597,11 +595,11 @@  EOF
 test_expect_success 'set up for test of subdir and sparse checkouts' '
 	mkdir done/sub &&
 	mkdir done/sub/sub &&
-	echo "sub" > done/sub/sub/file
+	echo "sub" > done/sub/sub/file &&
+	test-tool chmtime =-120 done/sub/sub/file done/sub/sub done/sub done
 '
 
 test_expect_success 'test sparse status with untracked cache and subdir' '
-	avoid_racy &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../status.actual &&
@@ -651,7 +649,6 @@  EOF
 '
 
 test_expect_success 'test sparse status again with untracked cache and subdir' '
-	avoid_racy &&
 	: >../trace.output &&
 	GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
 	git status --porcelain >../status.actual &&