Add unit tests.

tests/model_fields_/test_objectidfield.py

@@ -32,3 +32,10 @@ def test_to_python_invalid_value(self):
                 msg = f"['“{invalid_value}” value must be an Object Id.']"
                 with self.assertRaisesMessage(exceptions.ValidationError, msg):
                     ObjectIdField().to_python(invalid_value)
+
+    def test_get_prep_value_invalud_values(self):
+        for invalid_value in [3, "None", {}, []]:
+            with self.subTest(invalid_value=invalid_value):
+                msg = f"Field '{None}' expected an ObjectId but got {invalid_value!r}."
+                with self.assertRaisesMessage(ValueError, msg):
+                    ObjectIdField().get_prep_value(invalid_value)

tests/queries_/models.py

@@ -1,5 +1,7 @@
 from django.db import models
 
+from django_mongodb.fields import ObjectIdField
+
 
 class Author(models.Model):
     name = models.CharField(max_length=10)
@@ -14,3 +16,18 @@ class Book(models.Model):
 
     def __str__(self):
         return self.title
+
+
+class Tag(models.Model):
+    name = models.CharField(max_length=10)
+    parent = models.ForeignKey(
+        "self",
+        models.SET_NULL,
+        blank=True,
+        null=True,
+        related_name="children",
+    )
+    group_id = ObjectIdField(null=True)
+
+    def __str__(self):
+        return self.name

tests/queries_/test_objectid.py

@@ -0,0 +1,95 @@
+from bson import ObjectId
+from django.test import TestCase
+
+from .models import Tag
+
+
+class QueriesFilterByObjectId(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.group_id_str_1 = "1" * 24
+        cls.group_id_obj_1 = ObjectId(cls.group_id_str_1)
+        cls.group_id_str_2 = "2" * 24
+        cls.group_id_obj_2 = ObjectId(cls.group_id_str_2)
+
+        cls.t1 = Tag.objects.create(name="t1")
+        cls.t2 = Tag.objects.create(name="t2", parent=cls.t1)
+        cls.t3 = Tag.objects.create(name="t3", parent=cls.t1, group_id=cls.group_id_str_1)
+        cls.t4 = Tag.objects.create(name="t4", parent=cls.t3, group_id=cls.group_id_obj_2)
+        cls.t5 = Tag.objects.create(name="t5", parent=cls.t3)
+
+    def test_filter_group_id_is_null(self):
+        """Filter objects where group_id is not null"""
+        for value, expected in [(False, [self.t3, self.t4]), (True, [self.t1, self.t2, self.t5])]:
+            with self.subTest(object_id=value):
+                qs = Tag.objects.filter(group_id__isnull=value).order_by("name")
+                self.assertSequenceEqual(qs, expected)
+
+    def test_filter_group_id_equal_value(self):
+        """Filter by group_id with a specific value"""
+        for value in [self.group_id_str_1, self.group_id_obj_1]:
+            with self.subTest(object_id=value):
+                qs = Tag.objects.filter(group_id=value).order_by("name")
+                self.assertSequenceEqual(qs, [self.t3])
+
+    def test_filter_group_id_in_value(self):
+        """Filter by group_id where value is in a list"""
+        test_cases = [
+            [self.group_id_str_1, self.group_id_str_2],
+            [self.group_id_obj_1, self.group_id_obj_2],
+        ]
+        for values in test_cases:
+            with self.subTest(values=values):
+                qs = Tag.objects.filter(group_id__in=values).order_by("name")
+                self.assertSequenceEqual(qs, [self.t3, self.t4])
+
+    def test_filter_group_id_equal_subquery(self):
+        """Filter by group_id using a subquery"""
+        subquery = Tag.objects.filter(name="t3").values("group_id")
+        for value in [self.group_id_str_1, self.group_id_obj_1]:
+            with self.subTest(object_id=value):
+                qs = Tag.objects.filter(group_id__in=subquery).order_by("name")
+                self.assertSequenceEqual(qs, [self.t3])
+
+    def test_filter_group_id_in_subquery(self):
+        """Filter by group_id using a subquery with multiple values"""
+        subquery = Tag.objects.filter(name__in=["t3", "t4"]).values("group_id")
+        test_cases = [
+            [self.group_id_str_1, self.group_id_str_2],
+            [self.group_id_obj_1, self.group_id_obj_2],
+        ]
+        for values in test_cases:
+            with self.subTest(values=values):
+                qs = Tag.objects.filter(group_id__in=subquery).order_by("name")
+                self.assertSequenceEqual(qs, [self.t3, self.t4])
+
+    def test_union_children_to_select_parents(self):
+        """Union query to select parents of children based on group_id"""
+        child_group_ids = [self.group_id_str_1, self.group_id_obj_1]
+        for group_id in child_group_ids:
+            with self.subTest(group_id=group_id):
+                child_ids = Tag.objects.filter(group_id=group_id).values_list("id", flat=True)
+                parent_qs = (
+                    Tag.objects.filter(children__id__in=child_ids).distinct().order_by("name")
+                )
+                self.assertSequenceEqual(parent_qs, [self.t1])
+
+    def test_filter_group_id_union_with(self):
+        """Combine queries using union"""
+        test_cases = [
+            (self.group_id_str_1, self.group_id_str_2),
+            (self.group_id_obj_1, self.group_id_obj_2),
+        ]
+        for value1, value2 in test_cases:
+            with self.subTest(value1=value1, value2=value2):
+                qs_a = Tag.objects.filter(group_id=value1)
+                qs_b = Tag.objects.filter(group_id=value2)
+                union_qs = qs_a.union(qs_b).order_by("name")
+                self.assertSequenceEqual(union_qs, [self.t3, self.t4])
+
+    def test_invalid_object_id(self):
+        """Combine queries using union"""
+        value = "value1"
+        msg = f"Field 'group_id' expected an ObjectId but got '{value}'."
+        with self.assertRaisesMessage(ValueError, msg):
+            Tag.objects.filter(group_id=value)