@Test
public void mergeComplementaryColumns() {

    DataTable dt = new DataTable(1);
    dt.addRow("Vehicle type", "", "Brand");
    dt.addRow("Car", "Audi", "");
    dt.addRow("Car", "Mercedes", "");
    dt.addRow("Truck", "Volvo", "");
    dt.addRow("Truck", "DAF", "");
    DataTable merged = DataTableUtils.mergeComplementaryColumns(dt);
    assertThat(merged.getColumnsCount(), is(2));
    assertThat(merged.getRowsCount(), is(5));
    assertThat(merged.getColumn(0), is(Arrays.asList("Vehicle type", "Car", "Car", "Truck", "Truck")));
    assertThat(merged.getColumn(1), is(Arrays.asList("Brand", "Audi", "Mercedes", "Volvo", "DAF")));
    assertThat(dt.getColumnsCount(), is(3));
}