schema checks and unit tests.

tests/model_fields_/models.py

@@ -61,3 +61,10 @@ class Author(models.Model):
 class Book(models.Model):
     name = models.CharField(max_length=100)
     author = EmbeddedModelField(Author)
+
+
+class Library(models.Model):
+    name = models.CharField(max_length=100)
+    books = models.ManyToManyField("Book", related_name="libraries")
+    location = models.CharField(max_length=100, null=True, blank=True)
+    best_seller = models.CharField(max_length=100, null=True, blank=True)

tests/model_fields_/test_embedded_model.py

@@ -1,9 +1,18 @@
 import operator
-from datetime import timedelta
 from decimal import Decimal
 
 from django.core.exceptions import FieldDoesNotExist, ValidationError
-from django.db.models import ExpressionWrapper, F, IntegerField, Max, Model, Sum
+from django.db.models import (
+    Exists,
+    ExpressionWrapper,
+    F,
+    IntegerField,
+    Max,
+    Model,
+    OuterRef,
+    Subquery,
+    Sum,
+)
 from django.test import SimpleTestCase, TestCase
 
 from django_mongodb.fields import EmbeddedModelField
@@ -16,6 +25,7 @@
     DecimalParent,
     EmbeddedModel,
     EmbeddedModelFieldModel,
+    Library,
 )
 
 
@@ -185,9 +195,9 @@ def test_embedded_with_json_field(self):
             models[1:3],
         )
 
-    @staticmethod
-    def _truncate_ms(time):
-        return time - timedelta(microseconds=time.microsecond)
+    def truncate_ms(self, value):
+        """Truncate microsends to millisecond precision as supported by MongoDB."""
+        return value.replace(microsecond=(value.microsecond // 1000) * 1000)
 
     ################
     def test_ordering_by_embedded_field(self):
@@ -200,23 +210,26 @@ def test_ordering_by_embedded_field(self):
         self.assertSequenceEqual(query, expected)
 
     def test_ordering_grouping_by_embedded_field(self):
+        expected = sorted(
+            (
+                EmbeddedModelFieldModel.objects.create(simple=EmbeddedModel(someint=x))
+                for x in range(6)
+            ),
+            key=lambda x: x.simple.someint,
+        )
         query = (
             EmbeddedModelFieldModel.objects.annotate(
                 group=ExpressionWrapper(F("simple__someint") + 5, output_field=IntegerField())
             )
             .values("group")
-            .annotate(max_pk=Max("simple__auto_now"))
+            .annotate(max_auto_now=Max("simple__auto_now"))
             .order_by("simple__someint")
         )
-        query = [{**e, "max_pk": self._truncate_ms(e["max_pk"])} for e in query]
-        expected = [
-            EmbeddedModelFieldModel.objects.create(simple=EmbeddedModel(someint=x))
-            for x in range(6)
-        ]
+        query_response = [{**e, "max_auto_now": self.truncate_ms(e["max_auto_now"])} for e in query]
         self.assertSequenceEqual(
-            query,
+            query_response,
             [
-                {"group": e.simple.someint + 5, "max_pk": self._truncate_ms(e.simple.auto_now)}
+                {"group": e.simple.someint + 5, "max_auto_now": self.truncate_ms(e.simple.auto_now)}
                 for e in expected
             ],
         )
@@ -229,3 +242,62 @@ def test_ordering_grouping_by_sum(self):
             .order_by("sum")
         )
         self.assertQuerySetEqual(qs, [0, 2, 4, 6, 8, 10], operator.itemgetter("sum"))
+
+
+class SubqueryExistsTestCase(TestCase):
+    def setUp(self):
+        # Create test data
+        address1 = Address.objects.create(city="New York", state="NY", zip_code=10001)
+        address2 = Address.objects.create(city="Boston", state="MA", zip_code=20002)
+        author1 = Author.objects.create(name="Alice", age=30, address=address1)
+        author2 = Author.objects.create(name="Bob", age=40, address=address2)
+        book1 = Book.objects.create(name="Book A", author=author1)
+        book2 = Book.objects.create(name="Book B", author=author2)
+        Book.objects.create(name="Book C", author=author2)
+        Book.objects.create(name="Book D", author=author2)
+        Book.objects.create(name="Book E", author=author1)
+
+        library1 = Library.objects.create(
+            name="Central Library", location="Downtown", best_seller="Book A"
+        )
+        library2 = Library.objects.create(
+            name="Community Library", location="Suburbs", best_seller="Book A"
+        )
+
+        # Add books to libraries
+        library1.books.add(book1, book2)
+        library2.books.add(book2)
+
+    def test_exists_subquery(self):
+        subquery = Book.objects.filter(
+            author__name=OuterRef("name"), author__address__city="Boston"
+        )
+        queryset = Author.objects.filter(Exists(subquery))
+
+        self.assertEqual(queryset.count(), 1)
+
+    def test_in_subquery(self):
+        subquery = Author.objects.filter(age__gt=35).values("name")
+        queryset = Book.objects.filter(author__name__in=Subquery(subquery)).order_by("name")
+
+        self.assertEqual(queryset.count(), 3)
+        self.assertQuerySetEqual(queryset, ["Book B", "Book C", "Book D"], lambda book: book.name)
+
+    def test_range_query(self):
+        queryset = Author.objects.filter(age__range=(25, 45)).order_by("name")
+
+        self.assertEqual(queryset.count(), 2)
+        self.assertQuerySetEqual(queryset, ["Alice", "Bob"], lambda author: author.name)
+
+    def test_exists_with_foreign_object(self):
+        subquery = Library.objects.filter(best_seller=OuterRef("name"))
+        queryset = Book.objects.filter(Exists(subquery))
+
+        self.assertEqual(queryset.count(), 1)
+        self.assertEqual(queryset.first().name, "Book A")
+
+    def test_foreign_field_with_ranges(self):
+        queryset = Library.objects.filter(books__author__age__range=(25, 35))
+
+        self.assertEqual(queryset.count(), 1)
+        self.assertEqual(queryset.first().name, "Central Library")