why the test cant not pass?

FAIL Test named "test_replaceName" failed with message: "Unexpected error: 'length' 为空或不是对象".
Expected:
undefinedActual:
undefinedFAIL Test named "test_replaceElement" failed with message: "Unexpected error: 'length' 为空或不是对象".
Expected:
undefinedActual:
undefinedFAIL Test named "test_replaceAll_Class" failed with message: "Unexpected error: 'length' 为空或不是对象".
Expected:
undefinedActual:
undefinedFAIL Test named "test_replaceAll_Function" failed with message: "Unexpected error: 'length' 为空或不是对象".
Expected: