// instance for every unit test.
  MockWebServer server = new MockWebServer();

  // Schedule some responses.
  server.enqueue(new MockResponse().setBody("hello, world!"));
  server.enqueue(new MockResponse().setBody("sup, bra?"));
  server.enqueue(new MockResponse().setBody("yo dog"));

  // Start the server.
  server.start();

  // Ask the server for its URL. You'll need this to make HTTP requests.