t1800: add test to verify hook execution ordering

There is a documented expectation that configured hooks are
run before the hook from the hookdir. Add a test for it.

While at it, I noticed that `git hook list -h` runs twice
in the `git hook usage` test, so remove one invocation.

Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: 10ne1

t/t1800-hook.sh

@@ -25,7 +25,6 @@ test_expect_success 'git hook usage' '
 	test_expect_code 129 git hook &&
 	test_expect_code 129 git hook run &&
 	test_expect_code 129 git hook run -h &&
-	test_expect_code 129 git hook list -h &&
 	test_expect_code 129 git hook run --unknown 2>err &&
 	test_expect_code 129 git hook list &&
 	test_expect_code 129 git hook list -h &&
@@ -381,6 +380,34 @@ test_expect_success 'globally disabled hook can be re-enabled locally' '
 	test_cmp expected actual
 '
 
+test_expect_success 'configured hooks run before hookdir hook' '
+	setup_hookdir &&
+	test_config hook.first.event "pre-commit" &&
+	test_config hook.first.command "echo first" &&
+	test_config hook.second.event "pre-commit" &&
+	test_config hook.second.command "echo second" &&
+
+	cat >expected <<-\EOF &&
+	first
+	second
+	hook from hookdir
+	EOF
+
+	git hook list pre-commit >actual &&
+	test_cmp expected actual &&
+
+	# "Legacy Hook" is the output of the hookdir pre-commit script
+	# written by setup_hookdir() above.
+	cat >expected <<-\EOF &&
+	first
+	second
+	"Legacy Hook"
+	EOF
+
+	git hook run pre-commit 2>actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'git hook run a hook with a bad shebang' '
 	test_when_finished "rm -rf bad-hooks" &&
 	mkdir bad-hooks &&