Add serializer test

schema/field.go

@@ -175,10 +175,13 @@ func (schema *Schema) ParseField(fieldStruct reflect.StructField) *Field {
 	} else if name, ok := field.TagSettings["SERIALIZER"]; ok {
 		field.DataType = String
 		if strings.ToLower(name) == "json" {
-			field.Serializer = &JSONSerializer{}
+			field.Serializer = JSONSerializer{}
 		} else {
 			schema.err = fmt.Errorf("invalid serializer type %v", name)
 		}
+	} else if _, ok := field.TagSettings["JSON"]; ok {
+		field.DataType = String
+		field.Serializer = JSONSerializer{}
 	}
 
 	if num, ok := field.TagSettings["AUTOINCREMENTINCREMENT"]; ok {

schema/interfaces.go

@@ -77,7 +77,7 @@ func (JSONSerializer) Scan(ctx context.Context, field *Field, dst reflect.Value,
 
 // Value implements serializer interface
 func (JSONSerializer) Value(ctx context.Context, field *Field, dst reflect.Value, fieldValue interface{}) (interface{}, error) {
-	return fieldValue, nil
+	return json.Marshal(fieldValue)
 }
 
 // CreateClausesInterface create clauses interface

tests/serializer_test.go

@@ -0,0 +1,37 @@
+package tests_test
+
+import (
+	"testing"
+
+	"gorm.io/gorm"
+	. "gorm.io/gorm/utils/tests"
+)
+
+type SerializerStruct struct {
+	gorm.Model
+	Name  []byte `gorm:"json"`
+	Roles Roles  `gorm:"json"`
+}
+
+type Roles []string
+
+func TestSerializerJSON(t *testing.T) {
+	DB.Migrator().DropTable(&SerializerStruct{})
+	if err := DB.Migrator().AutoMigrate(&SerializerStruct{}); err != nil {
+		t.Fatalf("no error should happen when migrate scanner, valuer struct, got error %v", err)
+	}
+
+	data := SerializerStruct{
+		Name:  []byte("jinzhu"),
+		Roles: []string{"r1", "r2"},
+	}
+
+	if err := DB.Create(&data).Error; err != nil {
+		t.Fatalf("failed to create data, got error %v", err)
+	}
+
+	var result SerializerStruct
+	DB.First(&result, data.ID)
+
+	AssertEqual(t, result, data)
+}