add tests for rebasing of empty commits

Signed-off-by: Martin von Zweigbergk <martinvonz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3401-rebase-partial.sh

@@ -42,28 +42,4 @@ test_expect_success 'rebase --merge topic branch that was partially merged upstr
 	test_path_is_missing .git/rebase-merge
 '
 
-test_expect_success 'rebase ignores empty commit' '
-	git reset --hard A &&
-	git commit --allow-empty -m empty &&
-	test_commit D &&
-	git rebase C &&
-	test "$(git log --format=%s C..)" = "D"
-'
-
-test_expect_success 'rebase --keep-empty' '
-	git reset --hard D &&
-	git rebase --keep-empty C &&
-	test "$(git log --format=%s C..)" = "D
-empty"
-'
-
-test_expect_success 'rebase --keep-empty keeps empty even if already in upstream' '
-	git reset --hard A &&
-	git commit --allow-empty -m also-empty &&
-	git rebase --keep-empty D &&
-	test "$(git log --format=%s A..)" = "also-empty
-D
-empty"
-'
-
 test_done

t/t3421-rebase-topology-linear.sh

@@ -160,4 +160,62 @@ test_run_rebase success -m
 test_run_rebase success -i
 test_run_rebase success -p
 
+# a---b---c---j!
+#      \
+#       d---k!--l
+#
+# ! = empty
+test_expect_success 'setup of linear history for empty commit tests' '
+	git checkout c &&
+	make_empty j &&
+	git checkout d &&
+	make_empty k &&
+	test_commit l
+'
+
+test_run_rebase () {
+	result=$1
+	shift
+	test_expect_$result "rebase $* drops empty commit" "
+		reset_rebase &&
+		git rebase $* c l &&
+		test_cmp_rev c HEAD~2 &&
+		test_linear_range 'd l' c..
+	"
+}
+test_run_rebase success ''
+test_run_rebase success -m
+test_run_rebase success -i
+test_run_rebase success -p
+
+test_run_rebase () {
+	result=$1
+	shift
+	test_expect_$result "rebase $* --keep-empty" "
+		reset_rebase &&
+		git rebase $* --keep-empty c l &&
+		test_cmp_rev c HEAD~3 &&
+		test_linear_range 'd k l' c..
+	"
+}
+test_run_rebase success ''
+test_run_rebase failure -m
+test_run_rebase success -i
+test_run_rebase failure -p
+
+test_run_rebase () {
+	result=$1
+	shift
+	test_expect_$result "rebase $* --keep-empty keeps empty even if already in upstream" "
+		reset_rebase &&
+		git rebase $* --keep-empty j l &&
+		test_cmp_rev j HEAD~3 &&
+		test_linear_range 'd k l' j..
+	"
+}
+test_run_rebase success ''
+test_run_rebase failure -m
+test_run_rebase failure -i
+test_run_rebase failure -p
+
 test_done