@Test
public void testEmptyValue() {

    Map<String, List<String>> params = QueryStringParser.parseMap("a=&b=&c&d");
    assertEquals(4, params.size());
    assertEquals("", params.get("a").get(0));
    assertEquals("", params.get("b").get(0));
    assertEquals("", params.get("c").get(0));
    assertEquals("", params.get("d").get(0));
}