Example of using Relay Proxy to simulate latent connection in testing

testing_relay.go

// Error handling omitted for brevity

func TestGet(t *testing.T) {
        Convey("GIVEN the test server", t, func() {
                ts := httptest.NewServer(http.HandlerFunc(handler))
                Convey("GIVEN a slow connection which takes 4s to-from the server", func() {
                        // this delay is per trip, meaning it doubles for a round trip
                        delay := time.Duration(2) * time.Second
                        conn := relay.NewProxy(delay, ts)
                        Convey("WITH a client that times out after 3s", func() {
                                timeout := time.Duration(3) * time.Second
                                client := &Client{Timeout: timeout}
                                Convey("EXPECT the request to timeout in ~3s", func() {
                                        start := time.Now()
                                        resp, _ := client.Get(conn.URL)
                                        elapsed := time.Since(start)
                                        So(elapsed, ShouldAlmostEqual, timeout)
                                })
                        })      
                })
        })
}