@Test
public void testJoinWithComma() throws Exception {

    String[] src = new String[] { "1", "2", "3" };
    String arrayString = StringUtils.joinWithComma(src);
    Assert.assertEquals(arrayString, "1,2,3");
    arrayString = StringUtils.joinWithComma(new String[] {});
    Assert.assertEquals(arrayString, "");
    arrayString = StringUtils.joinWithComma(null, null);
    Assert.assertEquals(arrayString, "");
}