@Test
public void testJoinCollection() {

    Assert.assertEquals("", StringUtils
            .join(new ArrayList<String>(), ","));
    Assert.assertEquals("foo", StringUtils
            .join(new ArrayList<>(Arrays.asList("foo")), ","));
    Assert.assertEquals("foo,bar,baz", StringUtils
            .join(new ArrayList<>(
                    Arrays.asList("foo", "bar", "baz")), ","));
}