}

    @Test
    @DisplayName("Default ctor: null message/cause; toString is class name; type hierarchy")
    void defaultConstructor_hasNullMessageAndCause_andTypeHierarchy() {
        // Arrange & Act
        SMBProtocolDowngradeException ex = new SMBProtocolDowngradeException();

        // Assert - message and cause are null

Shinsuke Sugaya <******@****.***> 1755149504 +0900