fix(client): allow nil values authenticate

Either `consumer` or `credential` may be nil.

Author: lvermeire

client/client.go

@@ -127,25 +127,27 @@ func (c Client) GetConsumer() (consumer entities.Consumer, err error) {
 // for the current request. While both consumer and credential can be nil,
 // it is required that at least one of them exists. Otherwise this function will throw an error.
 func (c Client) Authenticate(consumer *entities.Consumer, credential *AuthenticatedCredential) error {
-	if consumer == nil {
-		return fmt.Errorf("Invalid consumer")
+	if consumer == nil && credential == nil {
+		return fmt.Errorf("either credential or consumer must be provided")
 	}
-	if credential == nil {
-		return fmt.Errorf("Invalid credential")
-	}
-	arg := &kong_plugin_protocol.AuthenticateArgs{
-		Consumer: &kong_plugin_protocol.Consumer{
+
+	arg := &kong_plugin_protocol.AuthenticateArgs{}
+	if consumer != nil {
+		arg.Consumer = &kong_plugin_protocol.Consumer{
 			Id:        consumer.Id,
 			CreatedAt: int64(consumer.CreatedAt),
 			Username:  consumer.Username,
 			CustomId:  consumer.CustomId,
 			Tags:      consumer.Tags,
-		},
-		Credential: &kong_plugin_protocol.AuthenticatedCredential{
+		}
+	}
+	if credential != nil {
+		arg.Credential = &kong_plugin_protocol.AuthenticatedCredential{
 			Id:         credential.Id,
 			ConsumerId: credential.ConsumerId,
-		},
+		}
 	}
+
 	err := c.Ask(`kong.client.authenticate`, arg, nil)
 	return err
 }

client/client_test.go

@@ -76,15 +76,48 @@ func TestLoadConsumer(t *testing.T) {
 	assert.Equal(t, entities.Consumer{Id: "001", Username: "Jon Doe"}, resp)
 }
 
-/*
-func TestGetConsumer(t *testing.T) {
-	assert.Equal(t, bridge.StepData{Method: "kong.client.get_consumer"}, getBack(func() { client.GetConsumer() }))
+func TestAuthenticate(t *testing.T) {
+	var consumer *entities.Consumer = &entities.Consumer{Id: "001", Username: "Jon Doe"}
+	var credential *AuthenticatedCredential = &AuthenticatedCredential{Id: "000:00", ConsumerId: "001"}
+
+	c := mockClient(t, []bridgetest.MockStep{
+		{Method: "kong.client.authenticate",
+			Args: &kong_plugin_protocol.AuthenticateArgs{
+				Consumer: &kong_plugin_protocol.Consumer{
+					Id:        consumer.Id,
+					CreatedAt: int64(consumer.CreatedAt),
+					Username:  consumer.Username,
+					CustomId:  consumer.CustomId,
+					Tags:      consumer.Tags,
+				},
+				Credential: &kong_plugin_protocol.AuthenticatedCredential{
+					Id:         credential.Id,
+					ConsumerId: credential.ConsumerId,
+				},
+			},
+			Ret: nil,
+		},
+	})
+
+	err := c.Authenticate(consumer, credential)
+
+	assert.NoError(t, err)
 }
 
-func TestAuthenticate(t *testing.T) {
+func TestAuthenticateNil(t *testing.T) {
 	var consumer *entities.Consumer = nil
 	var credential *AuthenticatedCredential = nil
-	assert.Equal(t, bridge.StepData{Method: "kong.client.authenticate", Args: []interface{}{consumer, credential}}, getBack(func() { client.Authenticate(nil, nil) }))
+
+	c := mockClient(t, nil)
+
+	err := c.Authenticate(consumer, credential)
+
+	assert.EqualError(t, err, "either credential or consumer must be provided")
+}
+
+/*
+func TestGetConsumer(t *testing.T) {
+	assert.Equal(t, bridge.StepData{Method: "kong.client.get_consumer"}, getBack(func() { client.GetConsumer() }))
 }
 
 func TestGetProtocol(t *testing.T) {