Add interface update and mock

Client.go

@@ -13,7 +13,7 @@ import (
 const Username = "pigeon"
 
 type ClientInterface interface {
-	GetAuthUrl(userId string, redirectUri string) (string, error)
+	GetAuthUrl(userId string, redirectUri string) (authUrl string, expireAt time.Time, err error)
 }
 
 type Client struct {

Client_test.go

@@ -2,6 +2,7 @@ package authorizer
 
 import (
 	"github.com/h2non/gock"
+	"github.com/kneu-messenger-pigeon/authorizer-client/mocks"
 	"github.com/kneu-messenger-pigeon/authorizer/dto"
 	"github.com/stretchr/testify/assert"
 	"net/url"
@@ -97,3 +98,17 @@ func TestClient_GetAuthUrl(t *testing.T) {
 	})
 
 }
+
+func TestIsInterface(t *testing.T) {
+	var client ClientInterface
+
+	t.Run("ClientInterface", func(t *testing.T) {
+		client = &Client{}
+		assert.NotNil(t, client)
+	})
+
+	t.Run("MockClientInterface", func(t *testing.T) {
+		client = mocks.NewClientInterface(t)
+		assert.NotNil(t, client)
+	})
+}