Viewing github.com/django/django-stable-4.1.x/tests/check_framework/test_model_field_deprecation.py

```
from django.core import checks
```
```
from django.db import models
```
```
from django.test import SimpleTestCase
```

from django.test.utils import isolate_apps

```
@isolate_apps("check_framework")
```

class TestDeprecatedField(SimpleTestCase):

```
    def test_default_details(self):
```
```
        class MyField(models.Field):
```

            system_check_deprecated_details = {}

```
        class Model(models.Model):
```
```
            name = MyField()
```
```
        model = Model()
```
```
        self.assertEqual(
```
```
            model.check(),
```
```
            [
```
```
                checks.Warning(
```

                    msg="MyField has been deprecated.",

                    obj=Model._meta.get_field("name"),

```
                    id="fields.WXXX",
```
```
                )
```
```
            ],
```
```
        )
```

    def test_user_specified_details(self):

```
        class MyField(models.Field):
```

            system_check_deprecated_details = {

                "msg": "This field is deprecated and will be removed soon.",

                "hint": "Use something else.",

```
                "id": "fields.W999",
```
```
            }
```
```
        class Model(models.Model):
```
```
            name = MyField()
```
```
        model = Model()
```
```
        self.assertEqual(
```
```
            model.check(),
```
```
            [
```
```
                checks.Warning(
```

                    msg="This field is deprecated and will be removed soon.",

                    hint="Use something else.",

                    obj=Model._meta.get_field("name"),

```
                    id="fields.W999",
```
```
                )
```
```
            ],
```
```
        )
```
```
@isolate_apps("check_framework")
```

class TestRemovedField(SimpleTestCase):

```
    def test_default_details(self):
```
```
        class MyField(models.Field):
```

            system_check_removed_details = {}

```
        class Model(models.Model):
```
```
            name = MyField()
```
```
        model = Model()
```
```
        self.assertEqual(
```
```
            model.check(),
```
```
            [
```
```
                checks.Error(
```
```
                    msg=(
```

                        "MyField has been removed except for support in historical "

```
                        "migrations."
```
```
                    ),
```

                    obj=Model._meta.get_field("name"),

```
                    id="fields.EXXX",
```
```
                )
```
```
            ],
```
```
        )
```

    def test_user_specified_details(self):

```
        class MyField(models.Field):
```

            system_check_removed_details = {

                "msg": "Support for this field is gone.",

                "hint": "Use something else.",

```
                "id": "fields.E999",
```
```
            }
```
```
        class Model(models.Model):
```
```
            name = MyField()
```
```
        model = Model()
```
```
        self.assertEqual(
```
```
            model.check(),
```
```
            [
```
```
                checks.Error(
```

                    msg="Support for this field is gone.",

                    hint="Use something else.",

                    obj=Model._meta.get_field("name"),

```
                    id="fields.E999",
```
```
                )
```
```
            ],
```
```
        )
```

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