    @Test
    public void successfulResponse() {

        App app = new App();
        GatewayResponse result = (GatewayResponse) app.handleRequest(null, null);
        assertEquals(result.getStatusCode(), 200);
        assertEquals(result.getHeaders().get("Content-Type"), "application/json");
        String content = result.getBody();
        assertNotNull(content);
        assertTrue(content.contains("\"message\""));
        assertTrue(content.contains("\"hello world\""));
        assertTrue(content.contains("\"location\""));
    }