Testing auth handler with apitest

I am trying to test the auth handler (gorilla mux):

func (env *Env) handleAuth(w http.ResponseWriter, r *http.Request) {
	log.Debug().Msg("auth login")
	_, err := gothic.CompleteUserAuth(w, r)
	if err != nil {
		gothic.BeginAuthHandler(w, r)
	}
}

I mean, it is simple enough that I probably do not need a test for it but nonetheless, I want one for reasons… The test code is

func Test_handleAuth(t *testing.T) {
	goth.UseProviders(
		google.New(
			os.Getenv("GOOGLE_KEY"),
			os.Getenv("GOOGLE_SECRET"),
			"http://localhost:8088/api/v1/auth/google/callback"),
	)
	env := Env{}
	apitest.New(). // configuration
			Report(apitest.SequenceDiagram()).
			HandlerFunc(env.handleAuth).
			Get("/api/v1/auth/google").
			Expect(t).
			Body(`ook`).
			Status(http.StatusOK).
			End()
}

This fails with the "you must select a provider" message. I thought the callback URL might be wrong so I changed it to 127.0.0.1 but got the same error.

What am I doing wrong?

Start with Test_handleAuth, the handleAuth entry point, and the goth.UseProviders setup; compare the requested /api/v1/auth/google path and callback configuration with how the provider is selected. Done means the test has a defined expected response and no longer fails with “you must select a provider,” or the required setup is documented.