assertEquals("capability check failed", ex.getMessage());
        verify(handle).hasCapability(42);
    }

    @Test
    @DisplayName("getSendBufferSize(): returns configured value")
    void getSendBufferSize_returns() throws Exception {
        // Arrange
        when(handle.getSendBufferSize()).thenReturn(8192);

        // Act
        int size = handle.getSendBufferSize();

        // Assert