Remove reference usage

Author: boekkooi-fresh

aggregate/changed.go

@@ -91,16 +91,14 @@ func (a *Changed) Metadata() metadata.Metadata {
 }
 
 // WithMetadata Returns new instance of the change with key and value added to metadata
-func (a *Changed) WithMetadata(key string, value interface{}) goengine.Message {
-	newAggregateChanged := *a
-	newAggregateChanged.metadata = metadata.WithValue(a.metadata, key, value)
+func (a Changed) WithMetadata(key string, value interface{}) goengine.Message {
+	a.metadata = metadata.WithValue(a.metadata, key, value)
 
-	return &newAggregateChanged
+	return &a
 }
 
-func (a *Changed) withVersion(version uint) *Changed {
-	newAggregateChanged := *a
-	newAggregateChanged.version = version
+func (a Changed) withVersion(version uint) *Changed {
+	a.version = version
 
-	return &newAggregateChanged
+	return &a
 }

aggregate/changed_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/hellofresh/goengine"
 	"github.com/hellofresh/goengine/aggregate"
 	"github.com/hellofresh/goengine/metadata"
@@ -127,3 +129,22 @@ func TestReconstituteChange(t *testing.T) {
 		}
 	})
 }
+
+func TestChanged_WithMetadata(t *testing.T) {
+	expectedMetadata := metadata.WithValue(metadata.New(), "test", "value")
+	msg, err := aggregate.ReconstituteChange(
+		aggregate.GenerateID(),
+		goengine.GenerateUUID(),
+		struct{}{},
+		metadata.New(),
+		time.Now(),
+		1,
+	)
+	require.NoError(t, err)
+
+	msgWithTest := msg.WithMetadata("test", "value")
+
+	assert.Equal(t, expectedMetadata, msgWithTest.Metadata())
+	assert.Equal(t, metadata.New(), msg.Metadata(), "Original metadata should not be changed")
+	assert.NotEqual(t, msg, msgWithTest, "Origional changed message should not be changed")
+}