@Override
  public String getGroupKeyColumnName(int groupKeyColumnIndex) {
    return _groupByColumns.get(groupKeyColumnIndex).asText();
  }
@Test
  public void testGetGroupKeyColumnName() {
    // Run the test
    final String result = _groupByResultSetUnderTest.getGroupKeyColumnName(0);

    // Verify the results
    assertEquals("testGroupColumn", result);
  }