stash: improve option parsing test coverage

In preparation for converting the stash command incrementally to
a builtin command, this patch improves test coverage of the option
parsing. Both for having too many parameters, or too few.

Signed-off-by: Joel Teichroeb <joel@teichroeb.net>
Signed-off-by: Paul-Sebastian Ungureanu <ungureanupaulsebastian@gmail.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3903-stash.sh

@@ -444,6 +444,36 @@ test_expect_failure 'stash file to directory' '
 	test foo = "$(cat file/file)"
 '
 
+test_expect_success 'giving too many ref arguments does not modify files' '
+	git stash clear &&
+	test_when_finished "git reset --hard HEAD" &&
+	echo foo >file2 &&
+	git stash &&
+	echo bar >file2 &&
+	git stash &&
+	test-tool chmtime =123456789 file2 &&
+	for type in apply pop "branch stash-branch"
+	do
+		test_must_fail git stash $type stash@{0} stash@{1} 2>err &&
+		test_i18ngrep "Too many revisions" err &&
+		test 123456789 = $(test-tool chmtime -g file2) || return 1
+	done
+'
+
+test_expect_success 'drop: too many arguments errors out (does nothing)' '
+	git stash list >expect &&
+	test_must_fail git stash drop stash@{0} stash@{1} 2>err &&
+	test_i18ngrep "Too many revisions" err &&
+	git stash list >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'show: too many arguments errors out (does nothing)' '
+	test_must_fail git stash show stash@{0} stash@{1} 2>err 1>out &&
+	test_i18ngrep "Too many revisions" err &&
+	test_must_be_empty out
+'
+
 test_expect_success 'stash create - no changes' '
 	git stash clear &&
 	test_when_finished "git reset --hard HEAD" &&
@@ -479,6 +509,11 @@ test_expect_success 'stash branch - stashes on stack, stash-like argument' '
 	test $(git ls-files --modified | wc -l) -eq 1
 '
 
+test_expect_success 'stash branch complains with no arguments' '
+	test_must_fail git stash branch 2>err &&
+	test_i18ngrep "No branch name specified" err
+'
+
 test_expect_success 'stash show format defaults to --stat' '
 	git stash clear &&
 	test_when_finished "git reset --hard HEAD" &&