assertEquals(cancelRequest, result);
        verify(request, times(1)).createCancel();
    }

    @Test
    @DisplayName("Test createCancel returns null when cancel not supported")
    void testCreateCancelReturnsNull() {
        // Given
        when(request.createCancel()).thenReturn(null);

        // When
        CommonServerMessageBlockRequest result = request.createCancel();

        // Then