DJANGO-REST测试：1）在测试串行器时无法分配外键值（2）Interger字段接受浮点值

Question

上下文：我正在编写用于测试DJANGO模型和Django-Rest API的序列化器的测试用例。

Models.py看起来像这样：

from django.db import models
import uuid

class User(models.Model):
    user_id = models.UUIDField(primary_key=True, unique=True, default=uuid.uuid4)
    first_name = models.CharField(max_length=100)
    second_name = models.CharField(max_length=100)

    def getuuid(self):
        return str(self.user_id)

class Workout(models.Model):
    user_id = models.ForeignKey(User, on_delete=models.DO_NOTHING, null=False, blank=False, default=None, db_column='user_id')
    hours = models.FloatField()
    class Meta:
        constraints = [
            models.CheckConstraint(
                check=models.Q(hours__gte=0),
                name="Hours should be positive"
            )
        ]

class Vacation(models.Model):
    user_id = models.ForeignKey(User, on_delete=models.DO_NOTHING, null=False, blank=False, default=None, db_column='user_id')
    times = models.IntegerField()
    class Meta:
        constraints = [
            models.CheckConstraint(
                check=models.Q(times__gte=1) & models.Q(times__lte=15),
                name="Valid range is 1 to 15 inclusive"
            )
        ]

serializer.py看起来像这样：

from rest_framework import serializers
from .models import User, Workout, Vacation

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model= User
        fields= '__all__'

class WorkoutSerializer(serializers.ModelSerializer):
    class Meta:
        model= Workout
        fields= '__all__'

class VacationSerializer(serializers.ModelSerializer):
    class Meta:
        model= Vacation
        fields= '__all__'

tests.py看起来像这样：

from django.test import TestCase
from .models import *
from .serializers import *

class UserTest(TestCase):
    @classmethod
    def setUpTestData(cls):
        super(UserTest, cls).setUpTestData()
        cls.u1 = User.objects.create(
            first_name = "Jack",
            second_name = "Mueller",
            #hours = 3.5,
            #times = 3
        )

        cls.w1 = Workout.objects.create(
            hours = 2,
            user_id = cls.u1
        )

        cls.t1 = Vacation.objects.create(
            times = 2.5,
            user_id = cls.u1
        )

        cls.w2_val = {
            "hours":6,
            "user_id": cls.u1
        }
        cls.w2 = Workout.objects.create(**cls.w2_val)
        cls.w2_ser = WorkoutSerializer(cls.w2)
        cls.w2_deser = WorkoutSerializer(data=cls.w2_val)


    def test_user_model(self):
        self.assertEquals(len(User.objects.all()), 1)
    
    def test_serializer(self):
        print(self.w2_deser.is_valid()) # return False
        print(self.w2_deser.errors)    # {'user_id': [ErrorDetail(string='“User object (3a598312-5f3d-4adb-b4fc-c415fb024e8a)” is not a valid UUID.', code='invalid')]} 

我的问题：

1. 为什么我会因 w2_deser.is_valid（）而false false？
2. 如何解决后续错误（w2_deser.errors）？我尝试设置user_id = cls.u1.user_id，这也无法解决问题。
3. 尽管 度假中的字段类被定义为整数，但它接受浮点值。这背后的原因是什么？我该如何解决？ （我尝试定义自定义验证器，但没有起作用。）

我已经在互联网上清除了解决方案/信息，并推荐了正式文档。但是，我的问题仍未解决。我是Django和休息的新手。因此，对此事的任何建议将受到欢迎。谢谢。