[PATCH v5] tests: use test_path_is_missing instead of '! test -f'

[Jayesh Daga <jayeshdaga99@gmail.com>]

Replace a raw '! test -f' check with test_path_is_missing.

The test_path_is_missing helper integrates with Git’s test
framework and produces clearer failure output. In contrast,
a plain shell '! test -f' check only reports a generic failure
status, which makes it harder to understand whether the file
unexpectedly exists or if another issue caused the test to fail.

It also avoids relying on negated shell conditions, making the
test easier to read and understand.

Signed-off-by: Jayesh Daga <jayeshdaga99@gmail.com>
---
v5:
- Clarify rationale for using test helper
- Explain diagnostic improvement and negation issues
- Address review comments on vague wording

v4:
- Correct commit message to match actual change
- Improve rationale (diagnostics, consistency)
- Move version notes below '---'
- Fix author name to match sign-off

v3:
- Fix commit message wording
---
 t/pack-refs-tests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/t/pack-refs-tests.sh b/t/pack-refs-tests.sh
index 2fdaccb6c7..4a85d96c6b 100644
--- a/t/pack-refs-tests.sh
+++ b/t/pack-refs-tests.sh
@@ -61,7 +61,7 @@ test_expect_success 'see if a branch still exists after git ${pack_refs} --prune
 test_expect_success 'see if git ${pack_refs} --prune remove ref files' '
 	git branch f &&
 	git ${pack_refs} --all --prune &&
-	! test -f .git/refs/heads/f
+	test_path_is_missing .git/refs/heads/f
 '
 
 test_expect_success 'see if git ${pack_refs} --prune removes empty dirs' '
-- 
2.43.0