Fix CI test to actually use the Postgres database

pyproject.toml

@@ -115,7 +115,7 @@ max_supported_python = "3.14"
 keep_full_version = true
 
 [tool.pytest.ini_options]
-addopts = "--tb=short --strict-markers -ra"
+addopts = "--tb=short --strict-markers -ra --no-migrations"
 testpaths = [ "tests" ]
 markers = [
   "requires_postgres: marks tests as requiring a PostgreSQL database backend",

rest_framework/test.py

@@ -1,11 +1,14 @@
 # Note that we import as `DjangoRequestFactory` and `DjangoClient` in order
 # to make it harder for the user to import the wrong thing without realizing.
 import io
+from contextlib import contextmanager
 from importlib import import_module
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.core.handlers.wsgi import WSGIHandler
+from django.core.signals import request_finished, request_started
+from django.db import close_old_connections
 from django.test import override_settings, testcases
 from django.test.client import Client as DjangoClient
 from django.test.client import ClientHandler
@@ -22,6 +25,21 @@ def force_authenticate(request, user=None, token=None):
     request._force_auth_token = token
 
 
+@contextmanager
+def _keep_connections_open():
+    """
+    Prevent Django from closing the database connection while a request
+    is dispatched, matching the behavior of Django's ClientHandler.
+    """
+    request_started.disconnect(close_old_connections)
+    request_finished.disconnect(close_old_connections)
+    try:
+        yield
+    finally:
+        request_started.connect(close_old_connections)
+        request_finished.connect(close_old_connections)
+
+
 if requests is not None:
     class HeaderDict(requests.packages.urllib3._collections.HTTPHeaderDict):
         def get_all(self, key, default):
@@ -90,7 +108,8 @@ def start_response(wsgi_status, wsgi_headers, exc_info=None):
 
             # Make the outgoing request via WSGI.
             environ = self.get_environ(request)
-            wsgi_response = self.app(environ, start_response)
+            with _keep_connections_open():
+                wsgi_response = self.app(environ, start_response)
 
             # Build the underlying urllib3.HTTPResponse
             raw_kwargs['body'] = io.BytesIO(b''.join(wsgi_response))

tests/conftest.py

@@ -3,7 +3,36 @@
 import dj_database_url
 import django
 import pytest
+from django.apps import apps
 from django.core import management
+from django.core.management.color import no_style
+from django.db import connection
+from django.test import TestCase, TransactionTestCase
+
+
+@pytest.fixture(autouse=True)
+def _reset_sequences(request):
+    """Reset all database sequences so PKs start from 1 in each test.
+
+    PostgreSQL sequences are non-transactional and persist across
+    TestCase's transaction rollbacks. This fixture ensures every test
+    gets predictable PKs starting from 1 regardless of execution order.
+    No-op on SQLite and skipped for tests that don't use the database.
+    """
+    if connection.vendor != 'postgresql':
+        return
+    # Only run for tests that actually have database access.
+    if not (request.cls and issubclass(request.cls, (TestCase, TransactionTestCase))):
+        if 'db' not in request.fixturenames and 'transactional_db' not in request.fixturenames:
+            return
+
+    table_names = set(connection.introspection.table_names())
+    models = [m for m in apps.get_models() if m._meta.db_table in table_names]
+    sql_list = connection.ops.sequence_reset_sql(no_style(), models)
+    if sql_list:
+        with connection.cursor() as cursor:
+            for sql in sql_list:
+                cursor.execute(sql)
 
 
 def pytest_addoption(parser):

tests/test_filters.py

@@ -45,7 +45,7 @@ def test_filter_queryset_raises_error(self):
 
 
 class SearchFilterModel(models.Model):
-    title = models.CharField(max_length=20)
+    title = models.CharField(max_length=25)
     text = models.CharField(max_length=100)
 
 

tests/test_relations_hyperlink.py

@@ -81,7 +81,7 @@ def setUp(self):
                 source.targets.add(target)
 
     def test_relative_hyperlinks(self):
-        queryset = ManyToManySource.objects.all()
+        queryset = ManyToManySource.objects.order_by('pk')
         serializer = ManyToManySourceSerializer(queryset, many=True, context={'request': None})
         expected = [
             {'url': '/manytomanysource/1/', 'name': 'source-1', 'targets': ['/manytomanytarget/1/']},
@@ -92,7 +92,7 @@ def test_relative_hyperlinks(self):
             assert serializer.data == expected
 
     def test_many_to_many_retrieve(self):
-        queryset = ManyToManySource.objects.all()
+        queryset = ManyToManySource.objects.order_by('pk')
         serializer = ManyToManySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanysource/1/', 'name': 'source-1', 'targets': ['http://testserver/manytomanytarget/1/']},
@@ -109,7 +109,7 @@ def test_many_to_many_retrieve_prefetch_related(self):
             serializer.data
 
     def test_reverse_many_to_many_retrieve(self):
-        queryset = ManyToManyTarget.objects.all()
+        queryset = ManyToManyTarget.objects.order_by('pk')
         serializer = ManyToManyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/manytomanysource/1/', 'http://testserver/manytomanysource/2/', 'http://testserver/manytomanysource/3/']},
@@ -128,7 +128,7 @@ def test_many_to_many_update(self):
         assert serializer.data == data
 
         # Ensure source 1 is updated, and everything else is as expected
-        queryset = ManyToManySource.objects.all()
+        queryset = ManyToManySource.objects.order_by('pk')
         serializer = ManyToManySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanysource/1/', 'name': 'source-1', 'targets': ['http://testserver/manytomanytarget/1/', 'http://testserver/manytomanytarget/2/', 'http://testserver/manytomanytarget/3/']},
@@ -145,7 +145,7 @@ def test_reverse_many_to_many_update(self):
         serializer.save()
         assert serializer.data == data
         # Ensure target 1 is updated, and everything else is as expected
-        queryset = ManyToManyTarget.objects.all()
+        queryset = ManyToManyTarget.objects.order_by('pk')
         serializer = ManyToManyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/manytomanysource/1/']},
@@ -164,7 +164,7 @@ def test_many_to_many_create(self):
         assert obj.name == 'source-4'
 
         # Ensure source 4 is added, and everything else is as expected
-        queryset = ManyToManySource.objects.all()
+        queryset = ManyToManySource.objects.order_by('pk')
         serializer = ManyToManySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanysource/1/', 'name': 'source-1', 'targets': ['http://testserver/manytomanytarget/1/']},
@@ -183,7 +183,7 @@ def test_reverse_many_to_many_create(self):
         assert obj.name == 'target-4'
 
         # Ensure target 4 is added, and everything else is as expected
-        queryset = ManyToManyTarget.objects.all()
+        queryset = ManyToManyTarget.objects.order_by('pk')
         serializer = ManyToManyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/manytomanytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/manytomanysource/1/', 'http://testserver/manytomanysource/2/', 'http://testserver/manytomanysource/3/']},
@@ -215,7 +215,7 @@ def setUp(self):
             source.save()
 
     def test_foreign_key_retrieve(self):
-        queryset = ForeignKeySource.objects.all()
+        queryset = ForeignKeySource.objects.order_by('pk')
         serializer = ForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/1/'},
@@ -226,7 +226,7 @@ def test_foreign_key_retrieve(self):
             assert serializer.data == expected
 
     def test_reverse_foreign_key_retrieve(self):
-        queryset = ForeignKeyTarget.objects.all()
+        queryset = ForeignKeyTarget.objects.order_by('pk')
         serializer = ForeignKeyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/foreignkeysource/1/', 'http://testserver/foreignkeysource/2/', 'http://testserver/foreignkeysource/3/']},
@@ -244,7 +244,7 @@ def test_foreign_key_update(self):
         assert serializer.data == data
 
         # Ensure source 1 is updated, and everything else is as expected
-        queryset = ForeignKeySource.objects.all()
+        queryset = ForeignKeySource.objects.order_by('pk')
         serializer = ForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/2/'},
@@ -267,7 +267,7 @@ def test_reverse_foreign_key_update(self):
         assert serializer.is_valid()
         # We shouldn't have saved anything to the db yet since save
         # hasn't been called.
-        queryset = ForeignKeyTarget.objects.all()
+        queryset = ForeignKeyTarget.objects.order_by('pk')
         new_serializer = ForeignKeyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/foreignkeysource/1/', 'http://testserver/foreignkeysource/2/', 'http://testserver/foreignkeysource/3/']},
@@ -279,7 +279,7 @@ def test_reverse_foreign_key_update(self):
         assert serializer.data == data
 
         # Ensure target 2 is update, and everything else is as expected
-        queryset = ForeignKeyTarget.objects.all()
+        queryset = ForeignKeyTarget.objects.order_by('pk')
         serializer = ForeignKeyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/foreignkeysource/2/']},
@@ -296,7 +296,7 @@ def test_foreign_key_create(self):
         assert obj.name == 'source-4'
 
         # Ensure source 1 is updated, and everything else is as expected
-        queryset = ForeignKeySource.objects.all()
+        queryset = ForeignKeySource.objects.order_by('pk')
         serializer = ForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/1/'},
@@ -315,7 +315,7 @@ def test_reverse_foreign_key_create(self):
         assert obj.name == 'target-3'
 
         # Ensure target 4 is added, and everything else is as expected
-        queryset = ForeignKeyTarget.objects.all()
+        queryset = ForeignKeyTarget.objects.order_by('pk')
         serializer = ForeignKeyTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/foreignkeytarget/1/', 'name': 'target-1', 'sources': ['http://testserver/foreignkeysource/2/']},
@@ -344,7 +344,7 @@ def setUp(self):
             source.save()
 
     def test_foreign_key_retrieve_with_null(self):
-        queryset = NullableForeignKeySource.objects.all()
+        queryset = NullableForeignKeySource.objects.order_by('pk')
         serializer = NullableForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/nullableforeignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/1/'},
@@ -362,7 +362,7 @@ def test_foreign_key_create_with_valid_null(self):
         assert obj.name == 'source-4'
 
         # Ensure source 4 is created, and everything else is as expected
-        queryset = NullableForeignKeySource.objects.all()
+        queryset = NullableForeignKeySource.objects.order_by('pk')
         serializer = NullableForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/nullableforeignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/1/'},
@@ -386,7 +386,7 @@ def test_foreign_key_create_with_valid_emptystring(self):
         assert obj.name == 'source-4'
 
         # Ensure source 4 is created, and everything else is as expected
-        queryset = NullableForeignKeySource.objects.all()
+        queryset = NullableForeignKeySource.objects.order_by('pk')
         serializer = NullableForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/nullableforeignkeysource/1/', 'name': 'source-1', 'target': 'http://testserver/foreignkeytarget/1/'},
@@ -405,7 +405,7 @@ def test_foreign_key_update_with_valid_null(self):
         assert serializer.data == data
 
         # Ensure source 1 is updated, and everything else is as expected
-        queryset = NullableForeignKeySource.objects.all()
+        queryset = NullableForeignKeySource.objects.order_by('pk')
         serializer = NullableForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/nullableforeignkeysource/1/', 'name': 'source-1', 'target': None},
@@ -428,7 +428,7 @@ def test_foreign_key_update_with_valid_emptystring(self):
         assert serializer.data == expected_data
 
         # Ensure source 1 is updated, and everything else is as expected
-        queryset = NullableForeignKeySource.objects.all()
+        queryset = NullableForeignKeySource.objects.order_by('pk')
         serializer = NullableForeignKeySourceSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/nullableforeignkeysource/1/', 'name': 'source-1', 'target': None},
@@ -449,7 +449,7 @@ def setUp(self):
         source.save()
 
     def test_reverse_foreign_key_retrieve_with_null(self):
-        queryset = OneToOneTarget.objects.all()
+        queryset = OneToOneTarget.objects.order_by('pk')
         serializer = NullableOneToOneTargetSerializer(queryset, many=True, context={'request': request})
         expected = [
             {'url': 'http://testserver/onetoonetarget/1/', 'name': 'target-1', 'nullable_source': 'http://testserver/nullableonetoonesource/1/'},