DRF ModelSerializer创建Booking时关联Room模型字段未更新问题

我为Booking模型编写了ModelSerializer，需要在其create方法中更新关联Room模型的对应字段，但实际运行时Booking对象成功创建，Room模型实例却未被更新，相关代码如下：

class BookingCreateUpdateSerializer(serializers.ModelSerializer):
    room = serializers.PrimaryKeyRelatedField(queryset=Room.objects.all())
    booking_status = serializers.ChoiceField(choices=BookingStatus.choices())

    class Meta:
        model = Booking
        fields = [
            # 省略其余字段定义
        ]

    def to_representation(self, instance):
        return BookingDetailSerializer(instance=instance,context=self.context).to_representation(instance)

    @transaction.atomic
    def create(self, validated_data):
        room = validated_data['room']
        booking_status = validated_data.pop('booking_status')
        room.booking_status = booking_status
        room.save()
        validated_data['room'] = room
        return super().create(validated_data)

预期结果 #

Room.booking_status 会被成功设置

实际结果 #

Room.booking_status 字段未发生变更

该问题出现在单元测试环节：在TestCase中测试时提前初始化了self.room = Room(...)实例，该内存实例不会自动同步数据库的最新修改，仅需要在执行断言前调用self.room.refresh_from_db()从数据库拉取最新值即可。

内容的提问来源于stack exchange，提问作者Shahzaib Akash