MockWebServer server = new MockWebServer(); MockResponse response = new MockResponse(); response.setResponseCode(200); response.setBody("Hello, mock server!"); server.start(); HttpUrl baseUrl = server.url("/api"); OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder() .url(baseUrl) .build(); Response serverResponse = client.newCall(request).execute(); assertEquals(200, serverResponse.code()); assertEquals("Hello, mock server!", serverResponse.body().string()); server.shutdown();