APITestCase Django中的模型冲突

Question

I'm trying to setup tests for my DRF API. I've got 2 models:

class Project(models.Model):
    name = models.CharField(max_length=300, unique=True)
    description = models.CharField(
        max_length=2000,
        blank=True,
        null=True,
        default=None
    )
    created_at = models.DateTimeField(auto_now_add=True)

class TemporaryUser(models.Model):
    username = models.CharField(max_length=400)
    hash_id = models.URLField(default=_generate_unique_hash, unique=True)
    project = models.ForeignKey(
        Project,
        on_delete=models.CASCADE,
        related_name='users'
    )

I've decided to separate setUp methods for every test file, so my 2 test files look like this:

test_projects.py

class ProjectViewsTest(APITestCase):
client = APIClient()

@classmethod
def setUpClass(cls):
    project = Project.objects.create(name="Test Project")
    cls.project_creation_date = datetime.now().strftime(
        '%Y-%m-%d %H:%M:%S'
    )
    Project.objects.create(
        name="Test Project #2", description='Testing Project Number 2'
    )

    session = QuestionSession.objects.create(project=project)
    cls.session_creation_date = datetime.now().strftime(
        '%Y-%m-%d %H:%M:%S'
    )

    Question.objects.create(
        description='Test Question #1',
        question_type='TEXT',
        answers_to_close=50,
        question_session=session
    )
    Question.objects.create(
        description='Test Question #2',
        question_type='TEXT',
        answers_to_close=50,
        question_session=session
    )
    Question.objects.create(
        description='Test Question #3',
        question_type='TEXT',
        answers_to_close=50,
        question_session=session
    )

@classmethod
def tearDownClass(cls):
    Project.objects.all().delete()

def test_projects_fetched_with_sessions_number(self):
    """Test multiple projects are fetched with sessions counter"""

    self.maxDiff = None

    response = self.client.get(
        'http://testserver/api/projects/', format='json'
    )

    self.assertEqual(response.status_code, 200)
    self.assertJSONEqual(
        response.content,
        {
            "projects": [
                {
                    "id": 1,
                    "name": "Test Project",
                    "description": None,
                    "sessions_number": 1,
                    "created_at": self.project_creation_date
                },
                {
                    "id": 2,
                    "name": "Test Project #2",
                    "description": "Testing Project Number 2",
                    "sessions_number": 0,
                    "created_at": self.project_creation_date
                }
            ]
        }
    )

def test_project_fetched_with_minified_sessions(self):
    """Test a project is fetched with minified sessions"""

    response = self.client.get(
        'http://testserver/api/projects/1/',
        format='json'
    )

    self.assertEqual(response.status_code, 200)
    self.assertJSONEqual(
        response.content,
        {
            "id": 1,
            "name": "Test Project",
            "created_at": self.project_creation_date,
            "sessions": [
                {
                    "id": 1,
                    "name": None,
                    "active": True,
                    "created_at": self.session_creation_date,
                    "priority": 0,
                    "questions_number": 3
                }
            ]
        }
    )

def test_project_creation(self):
    """Test project creation with/without passing description"""

    # POST with description
    response_1 = self.client.post(
        'http://testserver/api/projects/create/',
        format='json',
        data={"name": "Test Project #3", "description": "Another Project"}
    )

    # POST without description
    response_2 = self.client.post(
        'http://testserver/api/projects/create/',
        format='json',
        data={"name": "Test Project #4"}
    )

    self.assertEqual(response_1.status_code, 200)
    self.assertEqual(response_2.status_code, 200)

    self.assertJSONEqual(
        response_1.content,
        {
            'status': 'SUCCESS', 'id': 3,
            'message': 'Test Project #3 has been created successfully!'
        }
    )

    self.assertJSONEqual(
        response_2.content,
        {
            'status': 'SUCCESS', 'id': 4,
            'message': 'Test Project #4 has been created successfully!'
        }
    )

    project_1 = Project.objects.get(id=3)
    project_2 = Project.objects.get(id=4)

    self.assertEqual(project_1.description, "Another Project")
    self.assertEqual(project_2.description, "")

def test_project_deletion(self):
    """Test API call removes Project from database"""

    self.assertTrue(Project.objects.filter(id=1).exists())

    response = self.client.delete(
        'http://testserver/api/projects/1/delete/',
        format='json'
    )

    self.assertEqual(response.status_code, 200)
    self.assertJSONEqual(
        response.content,
        {
            'status': 'SUCCESS',
            'message': 'The project #1 has been deleted'
        }
    )

    self.assertFalse(Project.objects.filter(id=1).exists())

and test_users.py

class TemporaryUserViewsTest(APITestCase):
client = APIClient()

@classmethod
def setUpClass(cls):
    project = Project.objects.create(name="Test Project")
    Project.objects.create(
        name="Test Project #2", description='Testing Project Number 2'
    )

    TemporaryUser.objects.create(
        username="TestUser", project=project
    )

@classmethod
def tearDownClass(cls):
    Project.objects.all().delete()

def test_created_user_exists(self):
    """Tests if a user is unique per project"""

    response_1 = self.client.get(
        'http://testserver/api/projects/1/temp_user/TestUser/exists/',
        format='json'
    )

    response_2 = self.client.get(
        'http://testserver/api/projects/2/temp_user/TestUser/exists/',
        format='json'
    )

    self.assertEqual(response_1.status_code, 200)
    self.assertEqual(response_2.status_code, 200)

    self.assertJSONEqual(response_1.content, {"exists": True})
    self.assertJSONEqual(response_2.content, {"exists": False})

def test_user_created_for_specific_project(self):
    """Test if a user is created and exists for a specific project"""

    response_1 = self.client.post(
        'http://testserver/api/temp_user/create/',
        format='json',
        data={"username": "TestUser2", "project_id": 2}
    )

    user = TemporaryUser.objects.get(username='TestUser2')

    self.assertEqual(response_1.status_code, 200)
    self.assertEqual(json.loads(response_1.content)['created'], True)

    self.assertEqual(len(user.hash_id), 15)
    self.assertEqual(user.username, "TestUser2")

    response_2 = self.client.get(
        'http://testserver/api/projects/2/temp_user/TestUser2/exists/',
        format='json'
    )

    self.assertEqual(response_2.status_code, 200)
    self.assertJSONEqual(response_2.content, {"exists": True})

def test_user_not_created_twice(self):
    """Test a user can't be created twice"""

    response_1 = self.client.post(
        'http://testserver/api/temp_user/create/',
        format='json',
        data={"username": "TestUser3", "project_id": 1}
    )

    response_2 = self.client.post(
        'http://testserver/api/temp_user/create/',
        format='json',
        data={"username": "TestUser3", "project_id": 1}
    )

    self.assertEqual(response_1.status_code, 200)
    self.assertEqual(response_2.status_code, 200)

    self.assertEqual(json.loads(response_1.content)['created'], True)
    self.assertEqual(json.loads(response_2.content)['created'], False)

When I run these 2 tests separately like ./manage.py test core.tests.test_users and ./manage.py test core.tests.test_projects they work as expected, without any erros.

But when I run ./manage.py test core.tests it fails on test_user_not_created_twice() and test_user_created_for_specific_project() with:

Project matching query does not exist

What's wrong? I've even added Project.objects.all().delete() in tearDownClass methods, this didn't help. And also, is it a good practice to specify setUpClass methods like this?

Answer 1

I couldn't test this since some of the models in the tests weren't in the example, but I think it's likely that it's the hard-coded Project pk that you are referencing that is causing the issue - when running both test cases the first one will set up and then delete Project with pk #1 and then the second will set up and delete Project with pk #2

You could fix this by setting reset_sequences = True on your APITestCase classes, and then the second test case would be creating a Project with pk #1 again.

https://docs.djangoproject.com/en/2.2/topics/testing/advanced/#django.test.TransactionTestCase.reset_sequences

The better practice would be to hold on to a reference to your Project by doing self.project = Project.objects.create(name="Test Project") in your test setup code, and then using self.project.pk rather than hardcoding pk 1 in your test cases.

Also you should consider using setUpTestData rather than setUpClass for your use case (here's the source code for both ). No teardown should be required for data you add to the database in any setup as this all happens within a transaction that gets reverted after all test cases in the class have run.

It is assumed that individual tests read this class-level state, but don't modify it, so your test test_project_deletion() could cause other tests to fail since it deletes an object created at the class level.