first passing to clean and check

tests/test_prefetch_related_multiple_models_relation.py

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+from typing import List, Optional
+
+import databases
+import sqlalchemy
+from sqlalchemy import create_engine
+
+import ormar
+import pytest
+
+from tests.settings import DATABASE_URL
+
+db = databases.Database(DATABASE_URL)
+metadata = sqlalchemy.MetaData()
+
+
+class User(ormar.Model):
+    class Meta:
+        metadata = metadata
+        database = db
+        tablename = "test_users"
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=50)
+
+
+class Signup(ormar.Model):
+    class Meta:
+        metadata = metadata
+        database = db
+        tablename = "test_signup"
+
+    id: int = ormar.Integer(primary_key=True)
+
+
+class Session(ormar.Model):
+    class Meta:
+        metadata = metadata
+        database = db
+        tablename = "test_sessions"
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=255, index=True)
+    some_text: str = ormar.Text()
+    some_other_text: Optional[str] = ormar.Text(nullable=True)
+    teacher: Optional[User] = ormar.ForeignKey(
+        User, nullable=True, related_name="teaching"
+    )
+    students: Optional[List[User]] = ormar.ManyToMany(
+        User, through=Signup, related_name="attending"
+    )
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    engine = create_engine(DATABASE_URL)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+@pytest.mark.asyncio
+async def test_add_students():
+    for user_id in [1, 2, 3, 4, 5]:
+        await User.objects.create(name=f"User {user_id}")
+
+    for name, some_text, some_other_text in [
+        ("Session 1", "Some text 1", "Some other text 1"),
+        ("Session 2", "Some text 2", "Some other text 2"),
+        ("Session 3", "Some text 3", "Some other text 3"),
+        ("Session 4", "Some text 4", "Some other text 4"),
+        ("Session 5", "Some text 5", "Some other text 5"),
+    ]:
+        await Session(
+            name=name, some_text=some_text, some_other_text=some_other_text
+        ).save()
+
+    s1 = await Session.objects.get(pk=1)
+    s2 = await Session.objects.get(pk=2)
+
+    users = {}
+    for i in range(1, 6):
+        user = await User.objects.get(pk=i)
+        users[f"user_{i}"] = user
+        if i % 2 == 0:
+            await s1.students.add(user)
+        else:
+            await s2.students.add(user)
+
+    assert len(s1.students) > 0
+    assert len(s2.students) > 0
+
+    user = await User.objects.select_related("attending").get(pk=1)
+
+    assert user.attending is not None
+    assert len(user.attending) > 0
+
+    query = Session.objects.prefetch_related(
+        [
+            "students",
+            "teacher",
+        ]
+    )
+    sessions = await query.all()
+    assert len(sessions) == 5