Volleyer { Volleyer(RequestQueue requestQueue) { this.requestQueue = requestQueue; this.configuration = DefaultVolleyerConfigurationFactory.create(); } Volleyer(RequestQueue requestQueue); static Volleyer volleyer(); static synchronized Volleyer volleyer(RequestQueue requestQueue); GetBuilder get(String url); PostBuilder post(String url); PutBuilder put(String url); DeleteBuilder delete(String url); Settings settings();  }
@Test(expected = NullPointerException.class) public void volleyerShouldThrowNpeWhenRequestQueueIsNull() { volleyer(null); }
@Test public void volleyerShouldReturnVolleyerSameInstanceBySameRequestQueue() { assertThat(volleyer(requestQueue), is(volleyer(requestQueue))); }