perf/fsmonitor: use test_must_be_empty helper

From: Nipunn Koorapati <[email protected]>

Simplify test and make error messages more clear here. Per feedback from Junio in
33226af42b (t/perf/fsmonitor: improve error message if typoing hook name, 2020-10-26)

---
perf/fsmonitor: use test_must_be_empty helper

Simplify perf/fsmonitor test and make error messages more clear.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-799%2Fnipunn1313%2Fnk%2Ffsmonitor-test-cleanup-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-799/nipunn1313/nk/fsmonitor-test-cleanup-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/799

 t/perf/p7519-fsmonitor.sh | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

index 163a13bea3..9b43342806 100755
@@ -129,8 +129,7 @@ setup_for_fsmonitor() {
 
 	git config core.fsmonitor "$INTEGRATION_SCRIPT" &&
 	git update-index --fsmonitor 2>error &&
-	cat error &&
-	[ ! -s error ] # ensure no silent error
+	test_must_be_empty error  # ensure no silent error
 }
 
 test_perf_w_drop_caches () {

base-commit: b291b0a628020eedb10b6236d87fe25d295cea81

gitgitgadget

Thanks, Nipunn. This patch looks good to me.

-Stolee