fix for #354 - allow None for nullable field with choices

tests/test_model_definition/test_models.py

@@ -134,6 +134,26 @@ class Country(ormar.Model):
     )
 
 
+class NullableCountry(ormar.Model):
+    class Meta:
+        tablename = "country2"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=9, choices=country_name_choices, nullable=True)
+
+
+class NotNullableCountry(ormar.Model):
+    class Meta:
+        tablename = "country3"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=9, choices=country_name_choices, nullable=False)
+
+
 @pytest.fixture(autouse=True, scope="module")
 def create_test_database():
     engine = sqlalchemy.create_engine(DATABASE_URL)
@@ -538,6 +558,17 @@ async def test_model_choices():
             await Country.objects.filter(name="Belize").update(name="Vietnam")
 
 
+@pytest.mark.asyncio
+async def test_nullable_field_model_choices():
+    """Test that choices work properly for according to nullable setting"""
+    async with database:
+        c1 = await NullableCountry(name=None).save()
+        assert c1.name is None
+
+        with pytest.raises(ValueError):
+            await NotNullableCountry(name=None).save()
+
+
 @pytest.mark.asyncio
 async def test_start_and_end_filters():
     async with database: