Commit unit test

tests/models.py

@@ -2,6 +2,8 @@ import uuid
 
 from django.contrib.auth.models import User
 from django.db import models
+from django.db.models import QuerySet
+from django.db.models.manager import BaseManager
 from django.utils.translation import gettext_lazy as _
 
 
@@ -124,3 +126,27 @@ class OneToOnePKSource(RESTFrameworkModel):
     target = models.OneToOneField(
         OneToOneTarget, primary_key=True,
         related_name='required_source', on_delete=models.CASCADE)
+
+
+class CustomManagerModel(RESTFrameworkModel):
+    class CustomManager:
+        def __new__(cls, *args, **kwargs):
+            cls = BaseManager.from_queryset(
+                QuerySet
+            )
+            return cls
+
+    objects = CustomManager()()
+    # `CustomManager()` will return a `BaseManager` class.
+    # We need to instantiation it, so we write `CustomManager()()` here.
+
+    text = models.CharField(
+        max_length=100,
+        verbose_name=_("Text comes here"),
+        help_text=_("Text description.")
+    )
+
+    o2o_target = models.ForeignKey(OneToOneTarget,
+                                   help_text='OneToOneTarget',
+                                   verbose_name='OneToOneTarget',
+                                   on_delete=models.CASCADE)

tests/test_serializer_lists.py

@@ -6,6 +6,11 @@ from django.utils.datastructures import MultiValueDict
 
 from rest_framework import serializers
 from rest_framework.exceptions import ErrorDetail
+from tests.models import (
+    CustomManagerModel,
+    NullableOneToOneSource,
+    OneToOneTarget
+)
 
 
 class BasicObject:
@@ -683,3 +688,43 @@ class TestMaxMinLengthListSerializer:
         assert min_serializer.validated_data == input_data
 
         assert not max_min_serializer.is_valid()
+
+
+@pytest.mark.django_db()
+class TestToRepresentationManagerCheck:
+    """
+    https://github.com/encode/django-rest-framework/issues/8726
+    """
+
+    def setup(self):
+        class CustomManagerModelSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = CustomManagerModel
+                fields = '__all__'
+
+        class OneToOneTargetSerializer(serializers.ModelSerializer):
+            my_model = CustomManagerModelSerializer(many=True, source="custommanagermodel_set")
+
+            class Meta:
+                model = OneToOneTarget
+                fields = '__all__'
+                depth = 3
+
+        class NullableOneToOneSourceSerializer(serializers.ModelSerializer):
+            target = OneToOneTargetSerializer()
+
+            class Meta:
+                model = NullableOneToOneSource
+                fields = '__all__'
+
+        self.serializer = NullableOneToOneSourceSerializer
+
+    def test(self):
+        o2o_target = OneToOneTarget.objects.create(name='OneToOneTarget')
+        NullableOneToOneSource.objects.create(
+            name='NullableOneToOneSource',
+            target=o2o_target
+        )
+        queryset = NullableOneToOneSource.objects.all()
+        serializer = self.serializer(queryset, many=True)
+        assert serializer.data