first tests of orm [orm_tests]

Author: hjwp

conftest.py

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+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, clear_mappers
+
+from orm import metadata, start_mappers
+
+
+@pytest.fixture
+def in_memory_db():
+    engine = create_engine("sqlite:///:memory:")
+    metadata.create_all(engine)
+    return engine
+
+
+@pytest.fixture
+def session(in_memory_db):
+    start_mappers()
+    yield sessionmaker(bind=in_memory_db)()
+    clear_mappers()

test_orm.py

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+import model
+
+
+def test_orderline_mapper_can_load_lines(session):
+    session.execute(
+        "INSERT INTO order_lines (orderid, sku, qty) VALUES "
+        '("order1", "RED-CHAIR", 12),'
+        '("order1", "RED-TABLE", 13),'
+        '("order2", "BLUE-LIPSTICK", 14)'
+    )
+    expected = [
+        model.OrderLine("order1", "RED-CHAIR", 12),
+        model.OrderLine("order1", "RED-TABLE", 13),
+        model.OrderLine("order2", "BLUE-LIPSTICK", 14),
+    ]
+    assert session.query(model.OrderLine).all() == expected
+
+
+def test_orderline_mapper_can_save_lines(session):
+    new_line = model.OrderLine("order1", "DECORATIVE-WIDGET", 12)
+    session.add(new_line)
+    session.commit()
+
+    rows = list(session.execute('SELECT orderid, sku, qty FROM "order_lines"'))
+    assert rows == [("order1", "DECORATIVE-WIDGET", 12)]