diff --git a/tests/aggregation/tests.py b/tests/aggregation/tests.py
index c738cbb27e9..1f6baa70ff5 100644
--- a/tests/aggregation/tests.py
+++ b/tests/aggregation/tests.py
@@ -1,7 +1,6 @@
 import datetime
 import re
 from decimal import Decimal
-from unittest import skipIf
 
 from django.core.exceptions import FieldError
 from django.db import connection
@@ -1204,16 +1203,16 @@ class AggregateTestCase(TestCase):
         ])
 
     @skipUnlessDBFeature('supports_subqueries_in_group_by')
-    @skipIf(
-        connection.vendor == 'mysql' and 'ONLY_FULL_GROUP_BY' in connection.sql_mode,
-        'GROUP BY optimization does not work properly when ONLY_FULL_GROUP_BY '
-        'mode is enabled on MySQL, see #31331.',
-    )
     def test_aggregation_subquery_annotation_multivalued(self):
         """
         Subquery annotations must be included in the GROUP BY if they use
         potentially multivalued relations (contain the LOOKUP_SEP).
         """
+        if connection.vendor == 'mysql' and 'ONLY_FULL_GROUP_BY' in connection.sql_mode:
+            self.skipTest(
+                'GROUP BY optimization does not work properly when '
+                'ONLY_FULL_GROUP_BY mode is enabled on MySQL, see #31331.'
+            )
         subquery_qs = Author.objects.filter(
             pk=OuterRef('pk'),
             book__name=OuterRef('book__name'),
diff --git a/tests/annotations/tests.py b/tests/annotations/tests.py
index 3bf6a22bac0..3d00a02a114 100644
--- a/tests/annotations/tests.py
+++ b/tests/annotations/tests.py
@@ -1,6 +1,5 @@
 import datetime
 from decimal import Decimal
-from unittest import skipIf
 
 from django.core.exceptions import FieldDoesNotExist, FieldError
 from django.db import connection
@@ -647,12 +646,12 @@ class NonAggregateAnnotationTestCase(TestCase):
             datetime.date(2008, 11, 3),
         ])
 
-    @skipIf(
-        connection.vendor == 'mysql' and 'ONLY_FULL_GROUP_BY' in connection.sql_mode,
-        'GROUP BY optimization does not work properly when ONLY_FULL_GROUP_BY '
-        'mode is enabled on MySQL, see #31331.',
-    )
     def test_annotation_aggregate_with_m2o(self):
+        if connection.vendor == 'mysql' and 'ONLY_FULL_GROUP_BY' in connection.sql_mode:
+            self.skipTest(
+                'GROUP BY optimization does not work properly when '
+                'ONLY_FULL_GROUP_BY mode is enabled on MySQL, see #31331.'
+            )
         qs = Author.objects.filter(age__lt=30).annotate(
             max_pages=Case(
                 When(book_contact_set__isnull=True, then=Value(0)),
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 8e3b76d0437..d31a12e504f 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -2,7 +2,7 @@ import datetime
 import itertools
 import unittest
 from copy import copy
-from unittest import mock, skipIf
+from unittest import mock
 
 from django.core.management.color import no_style
 from django.db import (
@@ -710,13 +710,13 @@ class SchemaTests(TransactionTestCase):
             editor.alter_field(Foo, old_field, new_field, strict=True)
         Foo.objects.create()
 
-    @skipIf(
-        connection.vendor == 'mysql' and
-        connection.mysql_is_mariadb and
-        (10, 4, 3) < connection.mysql_version < (10, 5, 2),
-        'https://jira.mariadb.org/browse/MDEV-19598',
-    )
     def test_alter_not_unique_field_to_primary_key(self):
+        if (
+            connection.vendor == 'mysql' and
+            connection.mysql_is_mariadb and
+            (10, 4, 3) < connection.mysql_version < (10, 5, 2)
+        ):
+            self.skipTest('https://jira.mariadb.org/browse/MDEV-19598')
         # Create the table.
         with connection.schema_editor() as editor:
             editor.create_model(Author)
@@ -2950,17 +2950,17 @@ class SchemaTests(TransactionTestCase):
             editor.alter_field(Author, new_field, old_field, strict=True)
         self.assertEqual(self.get_constraints_for_column(Author, 'weight'), [])
 
-    @skipIf(
-        connection.vendor == 'mysql' and
-        connection.mysql_is_mariadb and
-        (10, 4, 12) < connection.mysql_version < (10, 5),
-        'https://jira.mariadb.org/browse/MDEV-22775',
-    )
     def test_alter_pk_with_self_referential_field(self):
         """
         Changing the primary key field name of a model with a self-referential
         foreign key (#26384).
         """
+        if (
+            connection.vendor == 'mysql' and
+            connection.mysql_is_mariadb and
+            (10, 4, 12) < connection.mysql_version < (10, 5)
+        ):
+            self.skipTest('https://jira.mariadb.org/browse/MDEV-22775')
         with connection.schema_editor() as editor:
             editor.create_model(Node)
         old_field = Node._meta.get_field('node_id')
diff --git a/tests/serializers/test_data.py b/tests/serializers/test_data.py
index 323cb13e821..9fbdd256fe3 100644
--- a/tests/serializers/test_data.py
+++ b/tests/serializers/test_data.py
@@ -378,21 +378,20 @@ if connection.features.interprets_empty_strings_as_nulls:
                          data[2]._meta.get_field('data').empty_strings_allowed and
                          data[3] is None)]
 
-# Regression test for #8651 -- a FK to an object with PK of 0
-# This won't work on MySQL without the NO_AUTO_VALUE_ON_ZERO SQL mode since it
-# won't let you create an object with an autoincrement primary key of 0.
-if connection.features.allows_auto_pk_0:
-    test_data.extend([
-        (data_obj, 0, Anchor, "Anchor 0"),
-        (fk_obj, 465, FKData, 0),
-    ])
-
 
 class SerializerDataTests(TestCase):
     pass
 
 
 def serializerTest(self, format):
+    # FK to an object with PK of 0. This won't work on MySQL without the
+    # NO_AUTO_VALUE_ON_ZERO SQL mode since it won't let you create an object
+    # with an autoincrement primary key of 0.
+    if connection.features.allows_auto_pk_0:
+        test_data.extend([
+            (data_obj, 0, Anchor, 'Anchor 0'),
+            (fk_obj, 465, FKData, 0),
+        ])
 
     # Create all the objects defined in the test data
     objects = []