dns-autoresolver/cmd/server/main_test.go

package main

import (
	"net/http"
	"net/http/httptest"
	"testing"
)

func TestIsAPIPath(t *testing.T) {
	cases := []struct {
		path string
		want bool
	}{
		{"/api", true},
		{"/api/", true},
		{"/api/domains", true},
		{"/", false},
		{"/domains/xyz", false},
		{"/apix", false},
	}
	for _, c := range cases {
		if got := isAPIPath(c.path); got != c.want {
			t.Errorf("isAPIPath(%q) = %v, want %v", c.path, got, c.want)
		}
	}
}

func TestBuildMux(t *testing.T) {
	var metricsHit, apiHit, webHit bool

	metricsHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		metricsHit = true
		w.WriteHeader(http.StatusOK)
	})
	apiRouter := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		apiHit = true
		w.WriteHeader(http.StatusOK)
	})
	webHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		webHit = true
		w.WriteHeader(http.StatusOK)
	})

	mux := buildMux(metricsHandler, apiRouter, webHandler)

	t.Run("healthz returns 200 ok", func(t *testing.T) {
		metricsHit, apiHit, webHit = false, false, false
		rr := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodGet, "/healthz", nil)
		mux.ServeHTTP(rr, req)
		if rr.Code != http.StatusOK {
			t.Fatalf("status = %d, want %d", rr.Code, http.StatusOK)
		}
		if rr.Body.String() != "ok" {
			t.Fatalf("body = %q, want %q", rr.Body.String(), "ok")
		}
		if metricsHit || apiHit || webHit {
			t.Fatalf("healthz must not fall through to other handlers")
		}
	})

	t.Run("metrics routed to metrics handler", func(t *testing.T) {
		metricsHit, apiHit, webHit = false, false, false
		rr := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
		mux.ServeHTTP(rr, req)
		if !metricsHit {
			t.Fatalf("expected metrics handler to be hit")
		}
	})

	t.Run("api path routed to api router", func(t *testing.T) {
		metricsHit, apiHit, webHit = false, false, false
		rr := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodGet, "/api/domains", nil)
		mux.ServeHTTP(rr, req)
		if !apiHit {
			t.Fatalf("expected api router to be hit")
		}
	})

	t.Run("other path routed to web handler", func(t *testing.T) {
		metricsHit, apiHit, webHit = false, false, false
		rr := httptest.NewRecorder()
		req := httptest.NewRequest(http.MethodGet, "/domains/xyz", nil)
		mux.ServeHTTP(rr, req)
		if !webHit {
			t.Fatalf("expected web handler to be hit")
		}
	})
}