@Test
public void testWrongColumnType() {

    DataSetLookup lookup = DataSetLookupFactory.newDataSetLookupBuilder()
            .group(DEPARTMENT)
            .column(DEPARTMENT)
            .column(EMPLOYEE)
            .buildLookup();
    ValidationError error = TWO_COLUMNS_GROUPED.check(lookup, METADATA);
    assertNotNull(error);
    assertEquals(error.getCode(), DataSetLookupConstraints.ERROR_COLUMN_TYPE);
    lookup = DataSetLookupFactory.newDataSetLookupBuilder()
            .group(DATE)
            .column(DATE)
            .column(EMPLOYEE)
            .buildLookup();
    error = TWO_COLUMNS_GROUPED.check(lookup, METADATA);
    assertNotNull(error);
    assertEquals(error.getCode(), DataSetLookupConstraints.ERROR_COLUMN_TYPE);
}