add sql_nullable param

tests/test_model_definition/test_overwriting_sql_nullable.py

@@ -0,0 +1,62 @@
+import sqlite3
+from typing import Optional
+
+import asyncpg
+import databases
+import pymysql
+import sqlalchemy
+from sqlalchemy import create_engine, text
+
+import ormar
+import pytest
+
+from tests.settings import DATABASE_URL
+
+db = databases.Database(DATABASE_URL, force_rollback=True)
+metadata = sqlalchemy.MetaData()
+
+
+class BaseMeta(ormar.ModelMeta):
+    metadata = metadata
+    database = db
+
+
+class PrimaryModel(ormar.Model):
+    class Meta(BaseMeta):
+        tablename = "primary_models"
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=255, index=True)
+    some_text: Optional[str] = ormar.Text(nullable=True, sql_nullable=False)
+    some_other_text: Optional[str] = ormar.Text(
+        nullable=True, sql_nullable=False, server_default=text("''")
+    )
+
+
+@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_create_models():
+    async with db:
+        primary = await PrimaryModel(
+            name="Foo", some_text="Bar", some_other_text="Baz"
+        ).save()
+        assert primary.id == 1
+
+        primary2 = await PrimaryModel(name="Foo2", some_text="Bar2").save()
+        assert primary2.id == 2
+
+        with pytest.raises(
+            (
+                sqlite3.IntegrityError,
+                pymysql.IntegrityError,
+                asyncpg.exceptions.NotNullViolationError,
+            )
+        ):
+            await PrimaryModel(name="Foo3").save()