Add implementation to persist orders in the db

app/database.py

@@ -0,0 +1,60 @@
+import sqlite3
+
+from app.types import Order
+
+
+def connect(connection_string):
+    return sqlite3.connect(
+        connection_string, detect_types=sqlite3.PARSE_DECLTYPES | sqlite3.PARSE_COLNAMES
+    )
+
+
+def apply_database_schema(connection):
+    connection.execute(
+        """
+    CREATE TABLE IF NOT EXISTS orders (
+      id integer primary key AUTOINCREMENT,
+      side varchar,
+      type varchar,
+      instrument char(12),
+      limit_price varchar,
+      quantity varchar,
+      created_at timestamp
+    );
+    """
+    )
+
+
+def insert_order(connection, order: Order):
+    result = connection.execute(
+        """
+    INSERT INTO orders (
+      side,
+      type,
+      instrument,
+      limit_price,
+      quantity,
+      created_at
+    ) VALUES (
+       :side,
+       :type,
+       :instrument,
+       :limit_price,
+       :quantity,
+       datetime()
+    ) returning id, created_at
+    """,
+        {
+            "side": order.side.value,
+            "type": order.type_.value,
+            "instrument": order.instrument,
+            "limit_price": str(order.limit_price),
+            "quantity": str(order.quantity),
+        },
+    )
+
+    returned_row = result.fetchone()
+    order.id_ = returned_row[0]
+    order.created_at = returned_row[1]
+
+    return order

tests/conftest.py

@@ -13,8 +13,12 @@ import pytest as pytest
 from starlette.testclient import TestClient
 
 from app.api import app
-
+import app.database as database
 
 @pytest.fixture
 def client() -> TestClient:
     return TestClient(app)
+
+@pytest.fixture
+def db_connection():
+    return database.connect("test.sqlite3")

tests/database_test.py

@@ -0,0 +1,32 @@
+from datetime import datetime
+
+import app.database as database
+from app.types import Order, OrderSide, OrderType
+
+
+def test_store_order(db_connection):
+    database.apply_database_schema(db_connection)
+
+    order = Order(
+        id="",
+        created_at=datetime.now(),
+        side=OrderSide.BUY,
+        type=OrderType.LIMIT,
+        instrument="123456789123",
+        limit_price=123.00,
+        quantity=1,
+    )
+
+    database.insert_order(db_connection, order)
+
+    record = db_connection.execute(
+        "SELECT * FROM orders where id = :id", {"id": order.id_}
+    ).fetchone()
+
+    assert record[0] == order.id_
+    assert record[1] == order.side.value
+    assert record[2] == order.type_.value
+    assert record[3] == order.instrument
+    assert record[4] == str(order.limit_price)
+    assert record[5] == str(order.quantity)
+    assert record[6] == order.created_at