@Override
    public Reader getCharacterStream(final int columnIndex) throws SQLException {
        return mergedResult.getCharacterStream(columnIndex);
    }
@Test
    void assertGetCharacterStream() throws SQLException {
        Reader reader = mock(Reader.class);
        when(mergedResult.getCharacterStream(1)).thenReturn(reader);
        assertThat(new MaskMergedResult(mock(MaskRule.class), mock(SelectStatementContext.class), mergedResult).getCharacterStream(1), is(reader));
    }