Verify forwarded proto in service test

internal/server/service_test.go

@@ -44,7 +44,13 @@ func TestService_RedirectToHTTPSWhenTLSRequired(t *testing.T) {
 }
 
 func TestService_DontRedirectToHTTPSWhenTLSAndPlainHTTPAllowed(t *testing.T) {
-	service := testCreateService(t, []string{"example.com"}, ServiceOptions{TLSEnabled: true, TLSDisableRedirect: true}, defaultTargetOptions)
+	var forwardedProto string
+
+	service := testCreateServiceWithHandler(t, []string{"example.com"}, ServiceOptions{TLSEnabled: true, TLSDisableRedirect: true}, defaultTargetOptions,
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			forwardedProto = r.Header.Get("X-Forwarded-Proto")
+		}),
+	)
 
 	require.True(t, service.options.TLSEnabled)
 
@@ -53,12 +59,14 @@ func TestService_DontRedirectToHTTPSWhenTLSAndPlainHTTPAllowed(t *testing.T) {
 	service.ServeHTTP(w, req)
 
 	require.Equal(t, http.StatusOK, w.Result().StatusCode)
+	assert.Equal(t, "http", forwardedProto)
 
 	req = httptest.NewRequest(http.MethodGet, "https://example.com", nil)
 	w = httptest.NewRecorder()
 	service.ServeHTTP(w, req)
 
 	require.Equal(t, http.StatusOK, w.Result().StatusCode)
+	assert.Equal(t, "https", forwardedProto)
 }
 
 func TestService_UseStaticTLSCertificateWhenConfigured(t *testing.T) {
@@ -154,7 +162,13 @@ func TestService_MarshallingState(t *testing.T) {
 }
 
 func testCreateService(t *testing.T, hosts []string, options ServiceOptions, targetOptions TargetOptions) *Service {
-	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
+	return testCreateServiceWithHandler(t, hosts, options, targetOptions,
+		http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}),
+	)
+}
+
+func testCreateServiceWithHandler(t *testing.T, hosts []string, options ServiceOptions, targetOptions TargetOptions, handler http.Handler) *Service {
+	server := httptest.NewServer(handler)
 	t.Cleanup(server.Close)
 
 	serverURL, err := url.Parse(server.URL)