From: "Michael Montalbo via GitGitGadget" <gitgitgadget@gmail•com>
To: git@vger•kernel.org
Cc: "D. Ben Knoble" <ben.knoble@gmail•com>,
Eric Sunshine <sunshine@sunshineco•com>,
Michael Montalbo <mmontalbo@gmail•com>,
Michael Montalbo <mmontalbo@gmail•com>
Subject: [PATCH 1/6] t/README: document test_grep helper
Date: Thu, 04 Jun 2026 07:45:53 +0000 [thread overview]
Message-ID: <43402040bf711e6266cfe664745099b8d3574255.1780559158.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2135.git.1780559158.gitgitgadget@gmail.com>
From: Michael Montalbo <mmontalbo@gmail•com>
test_grep is a wrapper around grep for test assertions that prints
the file contents on failure for easier debugging. It also accepts
'!' as its first argument for negation, which preserves the
diagnostic output that '! test_grep' would suppress.
Despite being widely used (and the preferred replacement for bare
grep in assertions), test_grep has no entry in t/README alongside
the other documented helpers like test_cmp and test_line_count.
Add one.
Signed-off-by: Michael Montalbo <mmontalbo@gmail•com>
---
t/README | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/t/README b/t/README
index adbbd9acf4..c12a1c317a 100644
--- a/t/README
+++ b/t/README
@@ -1039,6 +1039,27 @@ see test-lib-functions.sh for the full list and their options.
Check whether a file has the length it is expected to.
+ - test_grep [!] [<grep-options>] <pattern> <file>
+
+ Check whether <file> contains a line matching <pattern>, or
+ with '!' that no line matches. Use this instead of bare
+ 'grep <pattern> <file>' in test assertions. On failure,
+ test_grep prints the contents of <file> for easier debugging,
+ whereas a bare 'grep' would fail silently.
+
+ For negation, pass '!' as the first argument:
+
+ test_grep ! "^diff --git" actual
+
+ Do not negate by writing '! test_grep', as that suppresses the
+ diagnostic output.
+
+ test_grep should only be used as a test assertion. When grep
+ is used as a data filter (e.g. 'grep -v "^index" actual >filtered')
+ or inside a command substitution (e.g. '$(grep -c ...)'), plain
+ 'grep' is the right choice because the exit code is not the
+ assertion itself.
+
- test_path_is_file <path>
test_path_is_dir <path>
test_path_is_missing <path>
--
gitgitgadget
next prev parent reply other threads:[~2026-06-04 7:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 7:45 [PATCH 0/6] t: add lint-style.pl and convert grep to test_grep Michael Montalbo via GitGitGadget
2026-06-04 7:45 ` Michael Montalbo via GitGitGadget [this message]
2026-06-04 7:45 ` [PATCH 2/6] t: extract chainlint's parser into shared module Michael Montalbo via GitGitGadget
2026-06-04 7:45 ` [PATCH 3/6] t: fix Lexer line count for $() inside double-quoted strings Michael Montalbo via GitGitGadget
2026-06-04 7:45 ` [PATCH 4/6] t: add lint-style.pl with test_grep negation rule Michael Montalbo via GitGitGadget
2026-06-04 18:34 ` D. Ben Knoble
2026-06-04 19:36 ` Michael Montalbo
2026-06-04 7:45 ` [PATCH 5/6] t: fix grep assertions missing file arguments Michael Montalbo via GitGitGadget
2026-06-04 7:45 ` [PATCH 6/6] t: lint and convert grep assertions to test_grep Michael Montalbo via GitGitGadget
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