diff --git a/.coverage b/.coverage
deleted file mode 100644
index a5c0d9f86..000000000
Binary files a/.coverage and /dev/null differ
diff --git a/.gitignore b/.gitignore
index cf175d211..fb0cf92e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@ p38venv
 .idea
 .pytest_cache
 .mypy_cache
+.coverage
 *.pyc
 *.log
 test.db
diff --git a/docs/fastapi.md b/docs/fastapi.md
index 9ae1dadd6..d451feedc 100644
--- a/docs/fastapi.md
+++ b/docs/fastapi.md
@@ -45,7 +45,7 @@ Those models will be used insted of pydantic ones.
 Define your desired endpoints, note how `ormar` models are used both 
 as `response_model` and as a requests parameters.
 
-```python hl_lines="50-77"
+```python hl_lines="50-79"
 --8<-- "../docs_src/fastapi/docs001.py"
 ```
 
@@ -57,6 +57,23 @@ as `response_model` and as a requests parameters.
 
 ## Test the application
 
+### Run fastapi
+
+If you want to run this script and play with fastapi swagger install uvicorn first
+
+`pip install uvicorn`
+
+And launch the fastapi.
+
+`uvicorn <filename_without_extension>:app --reload`
+
+Now you can navigate to your browser (by default fastapi address is `127.0.0.1:8000/docs`) and play with the api.
+
+!!!info
+    You can read more about running fastapi in [fastapi][fastapi] docs. 
+
+### Test with pytest
+
 Here you have a sample test that will prove that everything works as intended.
 
 Be sure to create the tables first. If you are using pytest you can use a fixture.
@@ -109,9 +126,13 @@ def test_all_endpoints():
         assert len(items) == 0
 ```
 
+!!!tip
+    If you want to see more test cases and how to test ormar/fastapi see [tests][tests] directory in the github repo
+
 !!!info
     You can read more on testing fastapi in [fastapi][fastapi] docs. 
 
 [fastapi]: https://fastapi.tiangolo.com/
 [models]: ./models.md
-[database initialization]:  ../models/#database-initialization-migrations
\ No newline at end of file
+[database initialization]:  ../models/#database-initialization-migrations
+[tests]: https://github.com/collerek/ormar/tree/master/tests
\ No newline at end of file
diff --git a/docs/releases.md b/docs/releases.md
index c674fdb4f..75c68ae01 100644
--- a/docs/releases.md
+++ b/docs/releases.md
@@ -1,3 +1,10 @@
+# 0.3.9
+
+*  Fix json schema generation as of [#19][#19]
+*  Fix for not initialized ManyToMany relations in fastapi copies of ormar.Models
+*  Update docs in regard of fastapi use
+*  Add tests to verify fastapi/docs proper generation
+
 # 0.3.8
 
 *  Added possibility to provide alternative database column names with name parameter to all fields.
@@ -42,4 +49,7 @@ Add queryset level methods
 
 # 0.3.0
 
-* Added ManyToMany field and support for many to many relations
\ No newline at end of file
+* Added ManyToMany field and support for many to many relations
+
+
+[#19]: https://github.com/collerek/ormar/issues/19
\ No newline at end of file
diff --git a/docs_src/fastapi/docs001.py b/docs_src/fastapi/docs001.py
index 30ca75f5a..475756a48 100644
--- a/docs_src/fastapi/docs001.py
+++ b/docs_src/fastapi/docs001.py
@@ -72,6 +72,8 @@ async def get_item(item_id: int, item: Item):
 
 
 @app.delete("/items/{item_id}")
-async def delete_item(item_id: int, item: Item):
+async def delete_item(item_id: int, item: Item = None):
+    if item:
+        return {"deleted_rows": await item.delete()}
     item_db = await Item.objects.get(pk=item_id)
     return {"deleted_rows": await item_db.delete()}
diff --git a/mkdocs.yml b/mkdocs.yml
index a7b99e3d3..234f18d07 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -12,9 +12,9 @@ nav:
   - Release Notes: releases.md
 repo_name: collerek/ormar
 repo_url: https://github.com/collerek/ormar
-google_analytics:
-  - UA-72514911-3
-  - auto
+#google_analytics:
+#  - UA-72514911-3
+#  - auto
 theme:
   name: material
   highlightjs: true
diff --git a/ormar/__init__.py b/ormar/__init__.py
index 159fda57f..4aefddcda 100644
--- a/ormar/__init__.py
+++ b/ormar/__init__.py
@@ -28,7 +28,7 @@ def __repr__(self) -> str:
 
 Undefined = UndefinedType()
 
-__version__ = "0.3.8"
+__version__ = "0.3.9"
 __all__ = [
     "Integer",
     "BigInteger",
diff --git a/ormar/fields/foreign_key.py b/ormar/fields/foreign_key.py
index 2959f328a..854f83dcc 100644
--- a/ormar/fields/foreign_key.py
+++ b/ormar/fields/foreign_key.py
@@ -58,6 +58,7 @@ def ForeignKey(  # noqa CFQ002
         pydantic_only=False,
         default=None,
         server_default=None,
+        __pydantic_model__=to,
     )
 
     return type("ForeignKey", (ForeignKeyField, BaseField), namespace)
diff --git a/ormar/fields/many_to_many.py b/ormar/fields/many_to_many.py
index 0fed9e84f..1f73a0d18 100644
--- a/ormar/fields/many_to_many.py
+++ b/ormar/fields/many_to_many.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING, Type
+from typing import Dict, TYPE_CHECKING, Type
 
 from ormar.fields import BaseField
 from ormar.fields.foreign_key import ForeignKeyField
@@ -6,6 +6,8 @@
 if TYPE_CHECKING:  # pragma no cover
     from ormar.models import Model
 
+REF_PREFIX = "#/components/schemas/"
+
 
 def ManyToMany(
     to: Type["Model"],
@@ -31,6 +33,9 @@ def ManyToMany(
         pydantic_only=False,
         default=None,
         server_default=None,
+        __pydantic_model__=to,
+        # __origin__=List,
+        # __args__=[Optional[to]]
     )
 
     return type("ManyToMany", (ManyToManyField, BaseField), namespace)
@@ -38,3 +43,10 @@ def ManyToMany(
 
 class ManyToManyField(ForeignKeyField):
     through: Type["Model"]
+
+    @classmethod
+    def __modify_schema__(cls, field_schema: Dict) -> None:
+        field_schema["type"] = "array"
+        field_schema["title"] = cls.name.title()
+        field_schema["definitions"] = {f"{cls.to.__name__}": cls.to.schema()}
+        field_schema["items"] = {"$ref": f"{REF_PREFIX}{cls.to.__name__}"}
diff --git a/ormar/models/model.py b/ormar/models/model.py
index 3805a009f..eaf4935a6 100644
--- a/ormar/models/model.py
+++ b/ormar/models/model.py
@@ -145,7 +145,7 @@ async def update(self, **kwargs: Any) -> "Model":
 
         self_fields = self._extract_model_db_fields()
         self_fields.pop(self.get_column_name_from_alias(self.Meta.pkname))
-        self_fields = self.objects._translate_columns_to_aliases(self_fields)
+        self_fields = self.translate_columns_to_aliases(self_fields)
         expr = self.Meta.table.update().values(**self_fields)
         expr = expr.where(self.pk_column == getattr(self, self.Meta.pkname))
 
@@ -166,6 +166,6 @@ async def load(self) -> "Model":
                 "Instance was deleted from database and cannot be refreshed"
             )
         kwargs = dict(row)
-        kwargs = self.objects._translate_aliases_to_columns(kwargs)
+        kwargs = self.translate_aliases_to_columns(kwargs)
         self.from_dict(kwargs)
         return self
diff --git a/ormar/models/modelproxy.py b/ormar/models/modelproxy.py
index 760232d1c..c9651542d 100644
--- a/ormar/models/modelproxy.py
+++ b/ormar/models/modelproxy.py
@@ -5,7 +5,7 @@
 from ormar.exceptions import RelationshipInstanceError
 from ormar.fields import BaseField, ManyToManyField
 from ormar.fields.foreign_key import ForeignKeyField
-from ormar.models.metaclass import ModelMeta
+from ormar.models.metaclass import ModelMeta, expand_reverse_relationships
 
 if TYPE_CHECKING:  # pragma no cover
     from ormar import Model
@@ -112,9 +112,10 @@ def _extract_model_db_fields(self) -> Dict:
         return self_fields
 
     @staticmethod
-    def resolve_relation_name(
+    def resolve_relation_name(  # noqa CCR001
         item: Union["NewBaseModel", Type["NewBaseModel"]],
         related: Union["NewBaseModel", Type["NewBaseModel"]],
+        register_missing: bool = True,
     ) -> str:
         for name, field in item.Meta.model_fields.items():
             if issubclass(field, ForeignKeyField):
@@ -123,6 +124,13 @@ def resolve_relation_name(
                 # so we need to compare Meta too as this one is copied as is
                 if field.to == related.__class__ or field.to.Meta == related.Meta:
                     return name
+        # fallback for not registered relation
+        if register_missing:
+            expand_reverse_relationships(related.__class__)  # type: ignore
+            return ModelTableProxy.resolve_relation_name(
+                item, related, register_missing=False
+            )
+
         raise ValueError(
             f"No relation between {item.get_name()} and {related.get_name()}"
         )  # pragma nocover
@@ -140,6 +148,24 @@ def resolve_relation_field(
             )
         return to_field
 
+    @classmethod
+    def translate_columns_to_aliases(cls, new_kwargs: Dict) -> Dict:
+        for field_name, field in cls.Meta.model_fields.items():
+            if (
+                field_name in new_kwargs
+                and field.name is not None
+                and field.name != field_name
+            ):
+                new_kwargs[field.name] = new_kwargs.pop(field_name)
+        return new_kwargs
+
+    @classmethod
+    def translate_aliases_to_columns(cls, new_kwargs: Dict) -> Dict:
+        for field_name, field in cls.Meta.model_fields.items():
+            if field.name in new_kwargs and field.name != field_name:
+                new_kwargs[field_name] = new_kwargs.pop(field.name)
+        return new_kwargs
+
     @classmethod
     def merge_instances_list(cls, result_rows: List["Model"]) -> List["Model"]:
         merged_rows: List["Model"] = []
diff --git a/ormar/models/newbasemodel.py b/ormar/models/newbasemodel.py
index 88664fb3c..5cf28bcca 100644
--- a/ormar/models/newbasemodel.py
+++ b/ormar/models/newbasemodel.py
@@ -100,7 +100,7 @@ def __init__(self, *args: Any, **kwargs: Any) -> None:
             )
 
     def __setattr__(self, name: str, value: Any) -> None:  # noqa CCR001
-        if name in self.__slots__:
+        if name in ("_orm_id", "_orm_saved", "_orm"):
             object.__setattr__(self, name, value)
         elif name == "pk":
             object.__setattr__(self, self.Meta.pkname, value)
@@ -137,7 +137,7 @@ def _extract_related_model_instead_of_field(
         alias = self.get_column_alias(item)
         if alias in self._orm:
             return self._orm.get(alias)
-        return None
+        return None  # pragma no cover
 
     def __eq__(self, other: object) -> bool:
         if isinstance(other, NewBaseModel):
diff --git a/ormar/queryset/queryset.py b/ormar/queryset/queryset.py
index df1bc0139..a6c6b26fb 100644
--- a/ormar/queryset/queryset.py
+++ b/ormar/queryset/queryset.py
@@ -74,7 +74,7 @@ def _prepare_model_to_save(self, new_kwargs: dict) -> dict:
         new_kwargs = self._remove_pk_from_kwargs(new_kwargs)
         new_kwargs = self.model.substitute_models_with_pks(new_kwargs)
         new_kwargs = self._populate_default_values(new_kwargs)
-        new_kwargs = self._translate_columns_to_aliases(new_kwargs)
+        new_kwargs = self.model.translate_columns_to_aliases(new_kwargs)
         return new_kwargs
 
     def _populate_default_values(self, new_kwargs: dict) -> dict:
@@ -83,22 +83,6 @@ def _populate_default_values(self, new_kwargs: dict) -> dict:
                 new_kwargs[field_name] = field.get_default()
         return new_kwargs
 
-    def _translate_columns_to_aliases(self, new_kwargs: dict) -> dict:
-        for field_name, field in self.model_meta.model_fields.items():
-            if (
-                field_name in new_kwargs
-                and field.name is not None
-                and field.name != field_name
-            ):
-                new_kwargs[field.name] = new_kwargs.pop(field_name)
-        return new_kwargs
-
-    def _translate_aliases_to_columns(self, new_kwargs: dict) -> dict:
-        for field_name, field in self.model_meta.model_fields.items():
-            if field.name in new_kwargs and field.name != field_name:
-                new_kwargs[field_name] = new_kwargs.pop(field.name)
-        return new_kwargs
-
     def _remove_pk_from_kwargs(self, new_kwargs: dict) -> dict:
         pkname = self.model_meta.pkname
         pk = self.model_meta.model_fields[pkname]
@@ -207,7 +191,7 @@ async def count(self) -> int:
     async def update(self, each: bool = False, **kwargs: Any) -> int:
         self_fields = self.model.extract_db_own_fields()
         updates = {k: v for k, v in kwargs.items() if k in self_fields}
-        updates = self._translate_columns_to_aliases(updates)
+        updates = self.model.translate_columns_to_aliases(updates)
         if not each and not self.filter_clauses:
             raise QueryDefinitionError(
                 "You cannot update without filtering the queryset first. "
@@ -353,7 +337,7 @@ async def bulk_update(
                     f"{self.model.__name__} has to have {pk_name} filled."
                 )
             new_kwargs = self.model.substitute_models_with_pks(new_kwargs)
-            new_kwargs = self._translate_columns_to_aliases(new_kwargs)
+            new_kwargs = self.model.translate_columns_to_aliases(new_kwargs)
             new_kwargs = {"new_" + k: v for k, v in new_kwargs.items() if k in columns}
             ready_objects.append(new_kwargs)
 
diff --git a/ormar/relations/relation_manager.py b/ormar/relations/relation_manager.py
index a176bec07..6e7eb2491 100644
--- a/ormar/relations/relation_manager.py
+++ b/ormar/relations/relation_manager.py
@@ -40,6 +40,8 @@ def _add_relation(self, field: Type[BaseField]) -> None:
             to=field.to,
             through=getattr(field, "through", None),
         )
+        if field.name not in self._related_names:
+            self._related_names.append(field.name)
 
     def __contains__(self, item: str) -> bool:
         return item in self._related_names
diff --git a/ormar/relations/relation_proxy.py b/ormar/relations/relation_proxy.py
index 88130d58a..29e4b97f1 100644
--- a/ormar/relations/relation_proxy.py
+++ b/ormar/relations/relation_proxy.py
@@ -72,4 +72,6 @@ async def add(self, item: "Model") -> None:
         if self.relation._type == ormar.RelationType.MULTIPLE:
             await self.queryset_proxy.create_through_instance(item)
         rel_name = item.resolve_relation_name(item, self._owner)
+        if rel_name not in item._orm:
+            item._orm._add_relation(item.Meta.model_fields[rel_name])
         setattr(item, rel_name, self._owner)
diff --git a/tests/test_aliases.py b/tests/test_aliases.py
index f169c30eb..b48bb3f06 100644
--- a/tests/test_aliases.py
+++ b/tests/test_aliases.py
@@ -15,10 +15,10 @@ class Meta:
         metadata = metadata
         database = database
 
-    id: ormar.Integer(name='child_id', primary_key=True)
-    first_name: ormar.String(name='fname', max_length=100)
-    last_name: ormar.String(name='lname', max_length=100)
-    born_year: ormar.Integer(name='year_born', nullable=True)
+    id: ormar.Integer(name="child_id", primary_key=True)
+    first_name: ormar.String(name="fname", max_length=100)
+    last_name: ormar.String(name="lname", max_length=100)
+    born_year: ormar.Integer(name="year_born", nullable=True)
 
 
 class ArtistChildren(ormar.Model):
@@ -34,10 +34,10 @@ class Meta:
         metadata = metadata
         database = database
 
-    id: ormar.Integer(name='artist_id', primary_key=True)
-    first_name: ormar.String(name='fname', max_length=100)
-    last_name: ormar.String(name='lname', max_length=100)
-    born_year: ormar.Integer(name='year')
+    id: ormar.Integer(name="artist_id", primary_key=True)
+    first_name: ormar.String(name="fname", max_length=100)
+    last_name: ormar.String(name="lname", max_length=100)
+    born_year: ormar.Integer(name="year")
     children: ormar.ManyToMany(Child, through=ArtistChildren)
 
 
@@ -47,9 +47,9 @@ class Meta:
         metadata = metadata
         database = database
 
-    id: ormar.Integer(name='album_id', primary_key=True)
-    name: ormar.String(name='album_name', max_length=100)
-    artist: ormar.ForeignKey(Artist, name='artist_id')
+    id: ormar.Integer(name="album_id", primary_key=True)
+    name: ormar.String(name="album_name", max_length=100)
+    artist: ormar.ForeignKey(Artist, name="artist_id")
 
 
 @pytest.fixture(autouse=True, scope="module")
@@ -62,70 +62,87 @@ def create_test_database():
 
 
 def test_table_structure():
-    assert 'album_id' in [x.name for x in Album.Meta.table.columns]
-    assert 'album_name' in [x.name for x in Album.Meta.table.columns]
-    assert 'fname' in [x.name for x in Artist.Meta.table.columns]
-    assert 'lname' in [x.name for x in Artist.Meta.table.columns]
-    assert 'year' in [x.name for x in Artist.Meta.table.columns]
+    assert "album_id" in [x.name for x in Album.Meta.table.columns]
+    assert "album_name" in [x.name for x in Album.Meta.table.columns]
+    assert "fname" in [x.name for x in Artist.Meta.table.columns]
+    assert "lname" in [x.name for x in Artist.Meta.table.columns]
+    assert "year" in [x.name for x in Artist.Meta.table.columns]
 
 
 @pytest.mark.asyncio
 async def test_working_with_aliases():
     async with database:
         async with database.transaction(force_rollback=True):
-            artist = await Artist.objects.create(first_name='Ted', last_name='Mosbey', born_year=1975)
+            artist = await Artist.objects.create(
+                first_name="Ted", last_name="Mosbey", born_year=1975
+            )
             await Album.objects.create(name="Aunt Robin", artist=artist)
 
-            await artist.children.create(first_name='Son', last_name='1', born_year=1990)
-            await artist.children.create(first_name='Son', last_name='2', born_year=1995)
+            await artist.children.create(
+                first_name="Son", last_name="1", born_year=1990
+            )
+            await artist.children.create(
+                first_name="Son", last_name="2", born_year=1995
+            )
 
-            album = await Album.objects.select_related('artist').first()
-            assert album.artist.last_name == 'Mosbey'
+            album = await Album.objects.select_related("artist").first()
+            assert album.artist.last_name == "Mosbey"
 
             assert album.artist.id is not None
-            assert album.artist.first_name == 'Ted'
+            assert album.artist.first_name == "Ted"
             assert album.artist.born_year == 1975
 
-            assert album.name == 'Aunt Robin'
+            assert album.name == "Aunt Robin"
 
-            artist = await Artist.objects.select_related('children').get()
+            artist = await Artist.objects.select_related("children").get()
             assert len(artist.children) == 2
-            assert artist.children[0].first_name == 'Son'
-            assert artist.children[1].last_name == '2'
+            assert artist.children[0].first_name == "Son"
+            assert artist.children[1].last_name == "2"
 
-            await artist.update(last_name='Bundy')
+            await artist.update(last_name="Bundy")
             await Artist.objects.filter(pk=artist.pk).update(born_year=1974)
 
-            artist = await Artist.objects.select_related('children').get()
-            assert artist.last_name == 'Bundy'
+            artist = await Artist.objects.select_related("children").get()
+            assert artist.last_name == "Bundy"
             assert artist.born_year == 1974
 
-            artist = await Artist.objects.select_related('children').fields(
-                ['first_name', 'last_name', 'born_year', 'child__first_name', 'child__last_name']).get()
+            artist = (
+                await Artist.objects.select_related("children")
+                .fields(
+                    [
+                        "first_name",
+                        "last_name",
+                        "born_year",
+                        "child__first_name",
+                        "child__last_name",
+                    ]
+                )
+                .get()
+            )
             assert artist.children[0].born_year is None
 
 
 @pytest.mark.asyncio
 async def test_bulk_operations_and_fields():
     async with database:
-        d1 = Child(first_name='Daughter', last_name='1', born_year=1990)
-        d2 = Child(first_name='Daughter', last_name='2', born_year=1991)
+        d1 = Child(first_name="Daughter", last_name="1", born_year=1990)
+        d2 = Child(first_name="Daughter", last_name="2", born_year=1991)
         await Child.objects.bulk_create([d1, d2])
 
-        children = await Child.objects.filter(first_name='Daughter').all()
+        children = await Child.objects.filter(first_name="Daughter").all()
         assert len(children) == 2
-        assert children[0].last_name == '1'
+        assert children[0].last_name == "1"
 
         for child in children:
             child.born_year = child.born_year - 100
 
         await Child.objects.bulk_update(children)
 
-        children = await Child.objects.filter(first_name='Daughter').all()
+        children = await Child.objects.filter(first_name="Daughter").all()
         assert len(children) == 2
         assert children[0].born_year == 1890
 
-        children = await Child.objects.fields(['first_name', 'last_name']).all()
+        children = await Child.objects.fields(["first_name", "last_name"]).all()
         assert len(children) == 2
         for child in children:
             assert child.born_year is None
@@ -140,17 +157,21 @@ async def test_bulk_operations_and_fields():
 async def test_working_with_aliases_get_or_create():
     async with database:
         async with database.transaction(force_rollback=True):
-            artist = await Artist.objects.get_or_create(first_name='Teddy', last_name='Bear', born_year=2020)
+            artist = await Artist.objects.get_or_create(
+                first_name="Teddy", last_name="Bear", born_year=2020
+            )
             assert artist.pk is not None
 
-            artist2 = await Artist.objects.get_or_create(first_name='Teddy', last_name='Bear', born_year=2020)
+            artist2 = await Artist.objects.get_or_create(
+                first_name="Teddy", last_name="Bear", born_year=2020
+            )
             assert artist == artist2
 
             art3 = artist2.dict()
-            art3['born_year'] = 2019
+            art3["born_year"] = 2019
             await Artist.objects.update_or_create(**art3)
 
-            artist3 = await Artist.objects.get(last_name='Bear')
+            artist3 = await Artist.objects.get(last_name="Bear")
             assert artist3.born_year == 2019
 
             artists = await Artist.objects.all()
diff --git a/tests/test_fastapi_docs.py b/tests/test_fastapi_docs.py
new file mode 100644
index 000000000..030815f97
--- /dev/null
+++ b/tests/test_fastapi_docs.py
@@ -0,0 +1,135 @@
+from typing import List
+
+import databases
+import pytest
+import sqlalchemy
+from fastapi import FastAPI
+from starlette.testclient import TestClient
+
+import ormar
+from tests.settings import DATABASE_URL
+
+app = FastAPI()
+metadata = sqlalchemy.MetaData()
+database = databases.Database(DATABASE_URL, force_rollback=True)
+app.state.database = database
+
+
+@app.on_event("startup")
+async def startup() -> None:
+    database_ = app.state.database
+    if not database_.is_connected:
+        await database_.connect()
+
+
+@app.on_event("shutdown")
+async def shutdown() -> None:
+    database_ = app.state.database
+    if database_.is_connected:
+        await database_.disconnect()
+
+
+class LocalMeta:
+    metadata = metadata
+    database = database
+
+
+class Category(ormar.Model):
+    class Meta(LocalMeta):
+        tablename = "categories"
+
+    id: ormar.Integer(primary_key=True)
+    name: ormar.String(max_length=100)
+
+
+class ItemsXCategories(ormar.Model):
+    class Meta(LocalMeta):
+        tablename = "items_x_categories"
+
+
+class Item(ormar.Model):
+    class Meta(LocalMeta):
+        pass
+
+    id: ormar.Integer(primary_key=True)
+    name: ormar.String(max_length=100)
+    categories: ormar.ManyToMany(Category, through=ItemsXCategories)
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    engine = sqlalchemy.create_engine(DATABASE_URL)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+@app.get("/items/", response_model=List[Item])
+async def get_items():
+    items = await Item.objects.select_related("categories").all()
+    return items
+
+
+@app.post("/items/", response_model=Item)
+async def create_item(item: Item):
+    await item.save()
+    return item
+
+
+@app.post("/items/add_category/", response_model=Item)
+async def create_item(item: Item, category: Category):
+    await item.categories.add(category)
+    return item
+
+
+@app.post("/categories/", response_model=Category)
+async def create_category(category: Category):
+    await category.save()
+    return category
+
+
+def test_all_endpoints():
+    client = TestClient(app)
+    with client as client:
+        response = client.post("/categories/", json={"name": "test cat"})
+        category = response.json()
+        response = client.post("/categories/", json={"name": "test cat2"})
+        category2 = response.json()
+
+        response = client.post("/items/", json={"name": "test", "id": 1})
+        item = Item(**response.json())
+        assert item.pk is not None
+
+        response = client.post(
+            "/items/add_category/", json={"item": item.dict(), "category": category}
+        )
+        item = Item(**response.json())
+        assert len(item.categories) == 1
+        assert item.categories[0].name == "test cat"
+
+        client.post(
+            "/items/add_category/", json={"item": item.dict(), "category": category2}
+        )
+
+        response = client.get("/items/")
+        items = [Item(**item) for item in response.json()]
+        assert items[0] == item
+        assert len(items[0].categories) == 2
+        assert items[0].categories[0].name == "test cat"
+        assert items[0].categories[1].name == "test cat2"
+
+        response = client.get("/docs/")
+        assert response.status_code == 200
+        assert b"<title>FastAPI - Swagger UI</title>" in response.content
+
+
+def test_schema_modification():
+    schema = Item.schema()
+    assert schema["properties"]["categories"]["type"] == "array"
+    assert schema["properties"]["categories"]["title"] == "Categories"
+
+
+def test_schema_gen():
+    schema = app.openapi()
+    assert "Category" in schema["components"]["schemas"]
+    assert "Item" in schema["components"]["schemas"]
diff --git a/tests/test_models.py b/tests/test_models.py
index f33d855af..47b5d50e9 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -1,4 +1,5 @@
 import asyncio
+import uuid
 from datetime import datetime
 from typing import List
 
@@ -6,7 +7,6 @@
 import pydantic
 import pytest
 import sqlalchemy
-import uuid
 
 import ormar
 from ormar.exceptions import QueryDefinitionError, NoMatch
diff --git a/tests/test_more_reallife_fastapi.py b/tests/test_more_reallife_fastapi.py
index f0b9b884e..b538b5c5e 100644
--- a/tests/test_more_reallife_fastapi.py
+++ b/tests/test_more_reallife_fastapi.py
@@ -77,13 +77,15 @@ async def create_category(category: Category):
 
 
 @app.put("/items/{item_id}")
-async def get_item(item_id: int, item: Item):
+async def update_item(item_id: int, item: Item):
     item_db = await Item.objects.get(pk=item_id)
     return await item_db.update(**item.dict())
 
 
 @app.delete("/items/{item_id}")
-async def delete_item(item_id: int, item: Item):
+async def delete_item(item_id: int, item: Item = None):
+    if item:
+        return {"deleted_rows": await item.delete()}
     item_db = await Item.objects.get(pk=item_id)
     return {"deleted_rows": await item_db.delete()}
 
@@ -111,8 +113,20 @@ def test_all_endpoints():
         items = [Item(**item) for item in response.json()]
         assert items[0].name == "New name"
 
-        response = client.delete(f"/items/{item.pk}", json=item.dict())
+        response = client.delete(f"/items/{item.pk}")
         assert response.json().get("deleted_rows", "__UNDEFINED__") != "__UNDEFINED__"
         response = client.get("/items/")
         items = response.json()
         assert len(items) == 0
+
+        client.post("/items/", json={"name": "test_2", "id": 2, "category": category})
+        response = client.get("/items/")
+        items = response.json()
+        assert len(items) == 1
+
+        item = Item(**items[0])
+        response = client.delete(f"/items/{item.pk}", json=item.dict())
+        assert response.json().get("deleted_rows", "__UNDEFINED__") != "__UNDEFINED__"
+
+        response = client.get("/docs/")
+        assert response.status_code == 200