为什么单元测试一个图像字段使用SimpleUploadedFile创建多个图像?

Question

这是test .py

class ArticleModelTestCase(TestCase):
def setUp(self):
self.article = Article.objects.create(
title = 'Title test.',
content = 'Content test.',
date_posted = timezone.localtime(),
image = SimpleUploadedFile(
name = 'test_image.jpg',
content = b'',
content_type = 'image/jpeg'
)
)
def test_title(self):
self.assertEqual(self.article.title, 'Title test.')
def test_content(self):
self.assertEqual(self.article.content, 'Content test.')
def test_image_field(self):
self.assertEqual(self.article.image.name, 'test_image.jpg')

我得到了这个错误

> Creating test database for alias 'default'... System check identified
> no issues (0 silenced). .F.
> ====================================================================== FAIL: test_image_field (articles.tests.ArticleModelTestCase)
> ---------------------------------------------------------------------- Traceback (most recent call last):   File
> "/home/xxx/projects/xxxx/backend/articles/tests.py",
> line 27, in test_image_field
>     self.assertEqual(self.article.image.name, 'test_image.jpg') AssertionError: 'article_images/test_image_7U9qlax.jpg' !=
> 'test_image.jpg'
> - article_images/test_image_7U9qlax.jpg
> + test_image.jpg
> 
> 
> ---------------------------------------------------------------------- Ran 3 tests in 0.004s
> 
> FAILED (failures=1) Destroying test database for alias 'default'...

SimpleUploadedFile不仅创建了一个'test_image.jpg'，还创建了三个文件:

1. test_image.jpg
2. test_image_CWK5SDf.jpg
3. test_image_7U9qlax

每次我运行测试时，它总是会创建3个图像文件，随机单词和数字作为'test_image'之后的后缀。

它应该做的是创建一个名为'test_image'的图像文件。

为什么会发生这种情况，如何解决?

Answer 1

显然，因为有3个测试，def setUp被调用了3次，这就是为什么SimpleUploadedFile一直创建3个图像的原因。

这是我现在的新代码，它工作了

class ArticleModelTestCase(TestCase):
def setUp(self):
self.article = Article.objects.create(
title='Title test.',
content='Content test.',
date_posted=timezone.localtime(),
image=None
)
def tearDown(self):
if self.article.image:
os.remove(self.article.image.path)
def test_title(self):
self.assertEqual(self.article.title, 'Title test.')

def test_content(self):
self.assertEqual(self.article.content, 'Content test.')
def test_image_field(self):
test_image = SimpleUploadedFile(
name='test_image.jpg',
content=b'',
content_type='image/jpeg'
)
self.article.image = test_image
self.article.save()
self.assertEqual(self.article.image.name, 'article_images/test_image.jpg')