diff --git a/t/t6424-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index 89dd544f388..b6e424a427b 100755
--- a/t/t6424-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
@@ -71,7 +71,9 @@ test_expect_success 'ff update' '
 	git merge E^0 &&
 
 	test_must_fail git rev-parse HEAD:random_file &&
-	test "$(git diff --name-only --cached E)" = "random_file"
+	test "$(git diff --name-only --cached E)" = "random_file" &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file
 '
 
 test_expect_success 'ff update, important file modified' '
@@ -83,6 +85,8 @@ test_expect_success 'ff update, important file modified' '
 	git add subdir/e &&
 
 	test_must_fail git merge E^0 &&
+	test_path_is_file subdir/e &&
+	git rev-parse --verify :subdir/e &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -93,6 +97,8 @@ test_expect_success 'resolve, trivial' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge -s resolve C^0 &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -103,6 +109,8 @@ test_expect_success 'resolve, non-trivial' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge -s resolve D^0 &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -113,6 +121,8 @@ test_expect_success 'recursive' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge -s recursive C^0 &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -145,9 +155,12 @@ test_expect_success 'recursive, when file has staged changes not matching HEAD n
 	mkdir subdir &&
 	test_seq 1 10 >subdir/a &&
 	git add subdir/a &&
+	git rev-parse --verify :subdir/a >expect &&
 
 	# We have staged changes; merge should error out
 	test_must_fail git merge -s recursive E^0 2>err &&
+	git rev-parse --verify :subdir/a >actual &&
+	test_cmp expect actual &&
 	test_i18ngrep "changes to the following files would be overwritten" err
 '
 
@@ -158,9 +171,12 @@ test_expect_success 'recursive, when file has staged changes matching what a mer
 	mkdir subdir &&
 	test_seq 1 11 >subdir/a &&
 	git add subdir/a &&
+	git rev-parse --verify :subdir/a >expect &&
 
 	# We have staged changes; merge should error out
 	test_must_fail git merge -s recursive E^0 2>err &&
+	git rev-parse --verify :subdir/a >actual &&
+	test_cmp expect actual &&
 	test_i18ngrep "changes to the following files would be overwritten" err
 '
 
@@ -171,7 +187,9 @@ test_expect_success 'octopus, unrelated file touched' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge C^0 D^0 &&
-	test_path_is_missing .git/MERGE_HEAD
+	test_path_is_missing .git/MERGE_HEAD &&
+	git rev-parse --verify :random_file &&
+	test_path_exists random_file
 '
 
 test_expect_success 'octopus, related file removed' '
@@ -181,6 +199,8 @@ test_expect_success 'octopus, related file removed' '
 	git rm b &&
 
 	test_must_fail git merge C^0 D^0 &&
+	test_path_is_missing b &&
+	test_must_fail git rev-parse --verify :b &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -189,8 +209,12 @@ test_expect_success 'octopus, related file modified' '
 	git checkout B^0 &&
 
 	echo 12 >>a && git add a &&
+	git rev-parse --verify :a >expect &&
 
 	test_must_fail git merge C^0 D^0 &&
+	test_path_is_file a &&
+	git rev-parse --verify :a >actual &&
+	test_cmp expect actual &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -201,6 +225,8 @@ test_expect_success 'ours' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge -s ours C^0 &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
@@ -211,6 +237,8 @@ test_expect_success 'subtree' '
 	touch random_file && git add random_file &&
 
 	test_must_fail git merge -s subtree E^0 &&
+	test_path_is_file random_file &&
+	git rev-parse --verify :random_file &&
 	test_path_is_missing .git/MERGE_HEAD
 '
 
