@Test
public void testToCommaDelimitedString() {

    String value = toCommaDelimitedString(null);
    assertNull(value);
    value = toCommaDelimitedString(null, null);
    assertNull(value);
    value = toCommaDelimitedString("");
    assertEquals("", value);
    value = toCommaDelimitedString("one");
    assertEquals("one", value);
    value = toCommaDelimitedString("one", "two");
    assertEquals("one,two", value);
    value = toCommaDelimitedString("one", "two", "three");
    assertEquals("one,two,three", value);
}