2 files changed, 9 insertions, 6 deletions
diff --git a/tests/invalid_models_tests/test_ordinary_fields.py b/tests/invalid_models_tests/test_ordinary_fields.py
index 3922c835b9..9c7cf7f88c 100644
--- a/tests/invalid_models_tests/test_ordinary_fields.py
+++ b/tests/invalid_models_tests/test_ordinary_fields.py
@@ -2,7 +2,7 @@ import unittest
 
 from django.core.checks import Error, Warning as DjangoWarning
 from django.db import connection, models
-from django.test import SimpleTestCase, skipIfDBFeature
+from django.test import SimpleTestCase, TestCase, skipIfDBFeature
 from django.test.utils import isolate_apps, override_settings
 from django.utils.functional import lazy
 from django.utils.timezone import now
@@ -680,7 +680,7 @@ class TimeFieldTests(SimpleTestCase):
 
 
 @isolate_apps('invalid_models_tests')
-class TextFieldTests(SimpleTestCase):
+class TextFieldTests(TestCase):
 
     @skipIfDBFeature('supports_index_on_text_field')
     def test_max_length_warning(self):
diff --git a/tests/invalid_models_tests/test_relative_fields.py b/tests/invalid_models_tests/test_relative_fields.py
index cf1b3f737b..e68dd41c6f 100644
--- a/tests/invalid_models_tests/test_relative_fields.py
+++ b/tests/invalid_models_tests/test_relative_fields.py
@@ -1,7 +1,9 @@
+from unittest import mock
+
 from django.core.checks import Error, Warning as DjangoWarning
-from django.db import models
+from django.db import connection, models
 from django.db.models.fields.related import ForeignObject
-from django.test.testcases import SimpleTestCase, skipIfDBFeature
+from django.test.testcases import SimpleTestCase
 from django.test.utils import isolate_apps, override_settings
 
 
@@ -501,13 +503,14 @@ class RelativeFieldTests(SimpleTestCase):
             ),
         ])
 
-    @skipIfDBFeature('interprets_empty_strings_as_nulls')
     def test_nullable_primary_key(self):
         class Model(models.Model):
             field = models.IntegerField(primary_key=True, null=True)
 
         field = Model._meta.get_field('field')
-        self.assertEqual(field.check(), [
+        with mock.patch.object(connection.features, 'interprets_empty_strings_as_nulls', False):
+            results = field.check()
+        self.assertEqual(results, [
             Error(
                 'Primary keys must not have null=True.',
                 hint='Set null=False on the field, or remove primary_key=True argument.',