@Test
public void testToQueryString() throws Exception {

    Map<String, String> map = new HashMap<String, String>();
    map.put("key1", "value1");
    map.put("key2", "value2");
    String queryString = StringUtils.toQueryString(map);
    assertThat(queryString, containsString("key1=value1"));
    assertThat(queryString, containsString("key2=value2"));
}