Question

当我尝试运行单元测试时遇到问题。为什么会给我该错误消息？

来自tests.py的代码：

class CourseTestCase(TestCase):
    def create_category(name="English", imgpath="ImgPath"):
        return Category.objects.create(name=name, imgpath=imgpath)

    def setUp(self):
        Course.objects.create(
            name='English',
            description='Sample text',
            category_id=self.create_category().id,
            logo='Logo'
        )

    def test_course_category(self):
        english = Course.objects.get(name='English')
        self.assertEqual(english.category_id, 1)

Models.py：

class Category(models.Model):
    name = models.CharField(max_length=64)
    imgpath = models.CharField(max_length=64)

    def __str__(self):
        return str(self.name)

class Course(models.Model):
    name = models.CharField(max_length=64)
    description = models.TextField()
    category = models.ForeignKey(Category, on_delete=models.CASCADE, null=False)
    logo = models.TextField()

    def __str__(self):
        return str(self.name)

ValueError：无法分配“'Category'”：“ Course.category”必须是“ Category”实例。

Answer 1

尝试以下代码

class CourseTestCase(TestCase):

    def setUp(self):
        self.category = Category.objects.create(name="English", imgpath="ImgPath")
        self.course = Course.objects.create(
            name='English',
            description='Sample text',
            category=self.category,
            logo='Logo'
        )

    def test_course_category(self):
        english = Course.objects.get(name='English')
        self.assertEqual(english.category_id, self.category.id)

Answer 2

只需更改此：

category_id=self.create_category().id,

对此：

category=self.create_category(),

错误ValueError: Cannot assign "'Category'": "Course.category" must be a "Category" instance.告诉您属性category期望的是Category的类实例，而不是他的id的类实例

ValueError：无法分配“'Category'”：“ Course.category”必须是“ Category”实例

2 个答案: