bugreport tests: tighten up "git bugreport -s hooks" test

Amend a test added in 788a776069 (bugreport: collect list of
populated hooks, 2020-05-07) to "test_cmp" for the expected output,
instead of selectively using "grep" to check for specific things we
either expect or don't expect in the output.

As noted in a preceding commit our .git/hooks directory already
contains *.sample hooks, so we have no need to clobber the
prepare-commit-msg.sample hook in particular.

Instead we should assert that those *.sample hooks are not included in
the output, and for good measure let's add a new "unknown-hook", to
check that we only look through our own known hooks. See
cfe853e66b (hook-list.h: add a generated list of hooks, like
config-list.h, 2021-09-26) for how we generate that data.

We're intentionally not piping the "actual" output through "sort" or
similar, we'd also like to check that our reported hooks are sorted.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0091-bugreport.sh

@@ -60,18 +60,22 @@ test_expect_success 'can create leading directories outside of a git dir' '
 
 test_expect_success 'indicates populated hooks' '
 	test_when_finished rm git-bugreport-hooks.txt &&
-	test_when_finished rm -fr .git/hooks &&
-	rm -fr .git/hooks &&
-	mkdir .git/hooks &&
-	for hook in applypatch-msg prepare-commit-msg.sample
-	do
-		write_script ".git/hooks/$hook" <<-EOF || return 1
-		echo "hook $hook exists"
-		EOF
-	done &&
+
+	test_hook applypatch-msg <<-\EOF &&
+	true
+	EOF
+	test_hook unknown-hook <<-\EOF &&
+	true
+	EOF
 	git bugreport -s hooks &&
-	grep applypatch-msg git-bugreport-hooks.txt &&
-	! grep prepare-commit-msg git-bugreport-hooks.txt
+
+	sort >expect <<-\EOF &&
+	[Enabled Hooks]
+	applypatch-msg
+	EOF
+
+	sed -ne "/^\[Enabled Hooks\]$/,/^$/p" <git-bugreport-hooks.txt >actual &&
+	test_cmp expect actual
 '
 
 test_done