@Test
public void serializeTest() {

    Bbox bbox = new Bbox();
    bbox.setId(7);
    bbox.setBbox(12.3, 4.56, 78.9, 8.76);
    JsonElement serialized = bboxAdapter.serialize(bbox, Bbox.class, null);
    assertThat(serialized.toString(), is(equalTo("[12.3,4.56,78.9,8.76]")));
}