@Test
// tests appending at the end of the population
public void testAppendPopulation1(){

    Population[] inputPopulations = new Population[]{new SimplePopulation(), new SimplePopulation(), new SimplePopulation() };
    Population populationToAppend = new SimplePopulation();
    Population[] results = PopulationUtils.appendPopulation(inputPopulations, populationToAppend, true);
    assertEquals(4, results.length);
    assertSame(inputPopulations[0], results[0]);
    assertSame(inputPopulations[1], results[1]);
    assertSame(inputPopulations[2], results[2]);
    assertSame(populationToAppend, results[3]);
}