Add test for git rebase --abort

We expect git rebase --abort to come back to the original (pre-rebase)
head, independently from when it's run during a rebase.
Signed-off-by: NMike Hommey <mh@glandium.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t3407-rebase-abort.sh

+#!/bin/sh
+
+test_description='git rebase --abort tests'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	echo a > a &&
+	git add a &&
+	git commit -m a &&
+	git branch to-rebase &&
+
+	echo b > a &&
+	git commit -a -m b &&
+	echo c > a &&
+	git commit -a -m c &&
+
+	git checkout to-rebase &&
+	echo d > a &&
+	git commit -a -m "merge should fail on this" &&
+	echo e > a &&
+	git commit -a -m "merge should fail on this, too" &&
+	git branch pre-rebase
+'
+
+test_expect_success 'rebase --abort' '
+	test_must_fail git rebase master &&
+	git rebase --abort &&
+	test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase)
+'
+
+test_expect_failure 'rebase --abort after --skip' '
+	# Clean up the state from the previous one
+	git reset --hard pre-rebase
+	rm -rf .dotest
+
+	test_must_fail git rebase master &&
+	test_must_fail git rebase --skip &&
+	test $(git rev-parse HEAD) = $(git rev-parse master) &&
+	git rebase --abort &&
+	test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase)
+'
+
+test_expect_success 'rebase --abort after --continue' '
+	# Clean up the state from the previous one
+	git reset --hard pre-rebase
+	rm -rf .dotest
+
+	test_must_fail git rebase master &&
+	echo c > a &&
+	echo d >> a &&
+	git add a &&
+	test_must_fail git rebase --continue &&
+	test $(git rev-parse HEAD) != $(git rev-parse master) &&
+	git rebase --abort &&
+	test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase)
+'
+
+test_done