+commit_for_rebase_autosquash_setup () {
+ echo "first content line" >>foo &&
+ git add foo &&
+ cat >log <<EOF &&
+target message subject line
+
+target message body line 1
+target message body line 2
+EOF
+ git commit -F log &&
+ echo "second content line" >>foo &&
+ git add foo &&
+ git commit -m "intermediate commit" &&
+ echo "third content line" >>foo &&
+ git add foo
+}
+
+test_expect_success 'commit --fixup provides correct one-line commit message' '
+ commit_for_rebase_autosquash_setup &&
+ git commit --fixup HEAD~1 &&
+ commit_msg_is "fixup! target message subject line"
+'
+
+test_expect_success 'invalid message options when using --fixup' '
+ echo changes >>foo &&
+ echo "message" >log &&
+ git add foo &&
+ test_must_fail git commit --fixup HEAD~1 -C HEAD~2 &&
+ test_must_fail git commit --fixup HEAD~1 -c HEAD~2 &&
+ test_must_fail git commit --fixup HEAD~1 -m "cmdline message" &&
+ test_must_fail git commit --fixup HEAD~1 -F log
+'
+