change_batch_quantity on product, needed change to batch, also emit allocated event. [change_batch_model_layer]

hjwp · hjwp · commit f7350a8f45ef · 2019-11-20T21:12:36.000Z
diff --git a/src/allocation/model.py b/src/allocation/model.py
@@ -25,6 +25,14 @@ def allocate(self, line: OrderLine) -> str:
             self.events.append(events.OutOfStock(line.sku))
             return None
 
+    def change_batch_quantity(self, ref: str, qty: int):
+        batch = next(b for b in self.batches if b.reference == ref)
+        batch._purchased_quantity = qty
+        while batch.available_quantity < 0:
+            line = batch.deallocate_one()
+            self.events.append(
+                events.AllocationRequired(line.orderid, line.sku, line.qty)
+            )
 
 @dataclass(unsafe_hash=True)
 class OrderLine:
@@ -65,9 +73,8 @@ def allocate(self, line: OrderLine):
         if self.can_allocate(line):
             self._allocations.add(line)
 
-    def deallocate(self, line: OrderLine):
-        if line in self._allocations:
-            self._allocations.remove(line)
+    def deallocate_one(self) -> OrderLine:
+        return self._allocations.pop()
 
     @property
     def allocated_quantity(self) -> int:
diff --git a/tests/unit/test_batches.py b/tests/unit/test_batches.py
@@ -39,15 +39,3 @@ def test_allocation_is_idempotent():
     batch.allocate(line)
     batch.allocate(line)
     assert batch.available_quantity == 18
-
-def test_deallocate():
-    batch, line = make_batch_and_line("EXPENSIVE-FOOTSTOOL", 20, 2)
-    batch.allocate(line)
-    batch.deallocate(line)
-    assert batch.available_quantity == 20
-
-def test_can_only_deallocate_allocated_lines():
-    batch, unallocated_line = make_batch_and_line("DECORATIVE-TRINKET", 20, 2)
-    batch.deallocate(unallocated_line)
-    assert batch.available_quantity == 20
-
