2 files changed, 22 insertions, 22 deletions
diff --git a/tests/model_fields/test_autofield.py b/tests/model_fields/test_autofield.py
index 73220ae62b..db8e79e34b 100644
--- a/tests/model_fields/test_autofield.py
+++ b/tests/model_fields/test_autofield.py
@@ -1,32 +1,32 @@
-from django.test import TestCase
+from django.db import models
+from django.test import SimpleTestCase
 
 from .models import AutoModel, BigAutoModel, SmallAutoModel
+from .test_integerfield import (
+    BigIntegerFieldTests, IntegerFieldTests, SmallIntegerFieldTests,
+)
 
 
-class AutoFieldTests(TestCase):
+class AutoFieldTests(IntegerFieldTests):
     model = AutoModel
 
-    def test_invalid_value(self):
-        tests = [
-            (TypeError, ()),
-            (TypeError, []),
-            (TypeError, {}),
-            (TypeError, set()),
-            (TypeError, object()),
-            (TypeError, complex()),
-            (ValueError, 'non-numeric string'),
-            (ValueError, b'non-numeric byte-string'),
-        ]
-        for exception, value in tests:
-            with self.subTest(value=value):
-                msg = "Field 'value' expected a number but got %r." % (value,)
-                with self.assertRaisesMessage(exception, msg):
-                    self.model.objects.create(value=value)
 
-
-class BigAutoFieldTests(AutoFieldTests):
+class BigAutoFieldTests(BigIntegerFieldTests):
     model = BigAutoModel
 
 
-class SmallAutoFieldTests(AutoFieldTests):
+class SmallAutoFieldTests(SmallIntegerFieldTests):
     model = SmallAutoModel
+
+
+class AutoFieldInheritanceTests(SimpleTestCase):
+
+    def test_isinstance_of_autofield(self):
+        for field in (models.BigAutoField, models.SmallAutoField):
+            with self.subTest(field.__name__):
+                self.assertIsInstance(field(), models.AutoField)
+
+    def test_issubclass_of_autofield(self):
+        for field in (models.BigAutoField, models.SmallAutoField):
+            with self.subTest(field.__name__):
+                self.assertTrue(issubclass(field, models.AutoField))
diff --git a/tests/model_fields/test_integerfield.py b/tests/model_fields/test_integerfield.py
index c72cb48015..c0bb7627cf 100644
--- a/tests/model_fields/test_integerfield.py
+++ b/tests/model_fields/test_integerfield.py
@@ -125,7 +125,7 @@ class IntegerFieldTests(TestCase):
                         ranged_value_field.run_validators(max_backend_value + 1)
 
     def test_types(self):
-        instance = self.model(value=0)
+        instance = self.model(value=1)
         self.assertIsInstance(instance.value, int)
         instance.save()
         self.assertIsInstance(instance.value, int)