Chaining HTTP test servers, proxies and a switcher

proxy_switcher_chain.go

// Error handling omitted for brevity

ts1 := httptest.New(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprint(w, "Hello world!")
}))
ts2 := httptest.New(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprint(w, "Hello mars!")
}))
ts3 := httptest.New(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprint(w, "Hello pluto!")
}))

delay := time.Duration(0)
// a proxy sitting in front of ts3
p := relay.NewProxy(delay, ts3)
sw := relay.NewSwitcher(delay, []HTTPTestServer{ts1, ts2, p})

resp1, _ := http.Get(sw.URL) // hits ts1
resp2, _ := http.Get(sw.URL) // hits ts2
resp3, _ := http.Get(sw.URL) // hits p, which eventually hits ts3
resp4, _ := http.Get(sw.URL) // hits ts1