test out of stock exception [test_out_of_stock]

Author: hjwp

test_allocate.py

@@ -1,5 +1,6 @@
 from datetime import date, timedelta
-from model import allocate, OrderLine, Batch
+import pytest
+from model import allocate, OrderLine, Batch, OutOfStock
 
 today = date.today()
 tomorrow = today + timedelta(days=1)
@@ -36,3 +37,11 @@ def test_returns_allocated_batch_ref():
     line = OrderLine("oref", "HIGHBROW-POSTER", 10)
     allocation = allocate(line, [in_stock_batch, shipment_batch])
     assert allocation == in_stock_batch.reference
+
+
+def test_raises_out_of_stock_exception_if_cannot_allocate():
+    batch = Batch("batch1", "SMALL-FORK", 10, eta=today)
+    allocate(OrderLine("order1", "SMALL-FORK", 10), [batch])
+
+    with pytest.raises(OutOfStock, match="SMALL-FORK"):
+        allocate(OrderLine("order2", "SMALL-FORK", 1), [batch])