diff --git a/modules/core/test/test_io.cpp b/modules/core/test/test_io.cpp
index 3e1cf6d1f9..a36b212cdf 100644
--- a/modules/core/test/test_io.cpp
+++ b/modules/core/test/test_io.cpp
@@ -574,7 +574,7 @@ TEST(Core_InputOutput, FileStorageKey)
     EXPECT_NO_THROW(f << "key1" << "value1");
     EXPECT_NO_THROW(f << "_key2" << "value2");
     EXPECT_NO_THROW(f << "key_3" << "value3");
-    const std::string expected = "%YAML:1.0\nkey1: value1\n_key2: value2\nkey_3: value3\n";
+    const std::string expected = "%YAML 1.0\n---\nkey1: value1\n_key2: value2\nkey_3: value3\n";
     ASSERT_STREQ(f.releaseAndGetString().c_str(), expected.c_str());
 }