refactor: migrate to keyword-based repository config, add nested transactions and tests

examples/nested_transactions.py

@@ -0,0 +1,64 @@
+import asyncio
+
+from metaorm import BaseFilter, BaseRepository, BaseTable, Field, RepositorySettings
+
+
+class ProductTable(BaseTable, table=True):
+    __tablename__ = "products"
+
+    id: int | None = Field(default=None, primary_key=True)
+    name: str
+    price: float
+
+
+class ProductFilter(BaseFilter):
+    name: str | None = None
+
+
+class ProductRepository(BaseRepository, table=ProductTable, filter_=ProductFilter):
+    pass
+
+
+async def main() -> None:
+    settings = RepositorySettings(dsn="sqlite+aiosqlite:///:memory:")
+    repository = ProductRepository(settings=settings)
+
+    await repository.create_tables()
+
+    # Standalone nested transaction: rollback only the inner scope
+    try:
+        async with repository.nested_transaction():
+            await repository.create_item(ProductTable(name="Laptop", price=999.99))
+            await repository.create_item(ProductTable(name="Mouse", price=29.99))
+            raise ValueError("Simulated error inside nested transaction")
+    except ValueError:
+        pass
+
+    count = await repository.get_items_count()
+    print(f"Items after standalone nested rollback: {count}")  # 0
+
+    # Nested transaction inside an outer transaction
+    async with repository.transaction():
+        await repository.create_item(ProductTable(name="Keyboard", price=79.99))
+
+        try:
+            async with repository.nested_transaction():
+                await repository.create_item(
+                    ProductTable(name="Monitor", price=299.99),
+                )
+                raise ValueError("Nested rollback")
+        except ValueError:
+            pass
+
+        # Monitor is rolled back, Keyboard stays in the outer transaction
+        items = [item async for item in repository.get_items()]
+        print(f"Items after partial rollback: {len(items)}")  # 1
+        print(items[0].name)  # Keyboard
+
+    # Verify committed results
+    all_items = [item async for item in repository.get_items()]
+    print(f"Final items: {[item.name for item in all_items]}")  # ["Keyboard"]
+
+
+if __name__ == "__main__":
+    asyncio.run(main())