def METHOD_NAME(self, app):
    serv = MockServ(42423, bbox_aware_query_comparator=True)
    serv.expects(
        "/service?layers=foo,bar&width=256&version=1.1.1&bbox=-20037508.3428,0.0,0.0,20037508.3428&service=WMS&format=image%2Fpng&styles=&srs=EPSG%3A3857&request=GetMap&height=256"
    ).returns(TEST_TILE)
    with serv:
        resp = app.get(str(self.common_tile_req))
    assert resp.content_type == "image/png"
    data = BytesIO(resp.body)
    assert is_png(data)