diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 1c80148dd5..092aa26573 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -211,7 +211,7 @@ test_expect_success 'preserve merges with -p' '
 	git add unrelated-file &&
 	test_tick &&
 	git commit -m "unrelated" &&
-	git checkout -b to-be-rebased master &&
+	git checkout -b another-branch master &&
 	echo B > file1 &&
 	test_tick &&
 	git commit -m J file1 &&
@@ -220,12 +220,28 @@ test_expect_success 'preserve merges with -p' '
 	echo C > file1 &&
 	test_tick &&
 	git commit -m K file1 &&
+	echo D > file1 &&
+	test_tick &&
+	git commit -m L1 file1 &&
+	git checkout HEAD^ &&
+	echo 1 > unrelated-file &&
+	test_tick &&
+	git commit -m L2 unrelated-file &&
+	test_tick &&
+	git merge another-branch &&
+	echo E > file1 &&
+	test_tick &&
+	git commit -m M file1 &&
+	git checkout -b to-be-rebased &&
 	test_tick &&
 	git rebase -i -p --onto branch1 master &&
-	test $(git rev-parse HEAD^^2) = $(git rev-parse to-be-preserved) &&
-	test $(git rev-parse HEAD~3) = $(git rev-parse branch1) &&
-	test $(git show HEAD:file1) = C &&
-	test $(git show HEAD~2:file1) = B
+	test $(git rev-parse HEAD~6) = $(git rev-parse branch1) &&
+	test $(git rev-parse HEAD~4^2) = $(git rev-parse to-be-preserved) &&
+	test $(git rev-parse HEAD^^2^) = $(git rev-parse HEAD^^^) &&
+	test $(git show HEAD~5:file1) = B &&
+	test $(git show HEAD~3:file1) = C &&
+	test $(git show HEAD:file1) = E &&
+	test $(git show HEAD:unrelated-file) = 1
 '
 
 test_expect_success '--continue tries to commit' '