[PATCH v2] t6030: add test for git bisect skip started with --term* arguments

[Bagas Sanjaya <bagasdotme@gmail.com>]

Trygve Aaberge reported [1] git bisect breakage when the bisection
is started with --term* arguments (--term-new and --term-old). In that
case, skipping with `git bisect skip` should cause HEAD to be changed,
but actually the HEAD stayed same after skipping.

Let's add the test to catch the breakage. Because there isn't any fixes
yet, mark the test as test_expect_failure.

[1]: https://lore.kernel.org/git/20210418151459.GC10839@aaberge.net/

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
---
 Changes from v1 [1]:

   * Move the test to the the end of test script (test 74).
     v1 placed the test as test 26, and when I run the script, there
     are 9 more failed tests rather than just one (because such tests
     depended on previous ones). Now the test is placed together with
     similar tests (git bisect with --terms*).
   * Begin the test with git bisect reset, as with other nearby tests.

 [1]: https://lore.kernel.org/git/20210423070308.85275-1-bagasdotme@gmail.com/

 t/t6030-bisect-porcelain.sh | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 32bb66e1ed..b1b847ebbc 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -922,6 +922,19 @@ test_expect_success 'bisect start takes options and revs in any order' '
 	test_cmp expected actual
 '
 
+# Bisect is started with --term-new and --term-old arguments,
+# then skip. The HEAD should be changed.
+# FIXME: Mark this test as test_expect_failure. Remove the FIXME and
+# mark as test_expect_success when this test successes (fixed bug).
+test_expect_failure '"bisect skip: bisection is started with --term*"' '
+	git bisect reset &&
+	git bisect start --term-new=fixed --term-old=unfixed HEAD $HASH1 &&
+	HASH_SKIPPED_FROM=$(git rev-parse --verify HEAD) &&
+	git bisect skip &&
+	HASH_SKIPPED_TO=$(git rev-parse --verify HEAD) &&
+	test $HASH_SKIPPED_FROM != $HASH_SKIPPED_TO
+'
+
 test_expect_success 'git bisect reset cleans bisection state properly' '
 	git bisect reset &&
 	git bisect start &&

base-commit: 311531c9de557d25ac087c1637818bd2aad6eb3a
-- 
2.25.1