} else {
            assertNull(renewed, "renew() may return null for failed renewal");
        }
    }

    @Test
    @DisplayName("Mockito: verify renew() interaction and return value")
    void mockitoInteraction(@Mock CredentialsInternal returned, @Mock SmbRenewableCredentials renewable) {
        // Arrange: stub renew() to return a mocked CredentialsInternal
        when(renewable.renew()).thenReturn(returned);