make sure deallocation fixes view model too [deallocation_to_readmodel]

Author: hjwp

src/allocation/domain/events.py

@@ -11,6 +11,12 @@ class Allocated(Event):
     qty: int
     batchref: str
 
+@dataclass
+class Deallocated(Event):
+    orderid: str
+    sku: str
+    qty: int
+
 @dataclass
 class OutOfStock(Event):
     sku: str

src/allocation/domain/model.py

@@ -35,7 +35,7 @@ def change_batch_quantity(self, ref: str, qty: int):
         while batch.available_quantity < 0:
             line = batch.deallocate_one()
             self.events.append(
-                commands.Allocate(line.orderid, line.sku, line.qty)
+                events.Deallocated(line.orderid, line.sku, line.qty)
             )
 
 @dataclass(unsafe_hash=True)

src/allocation/service_layer/handlers.py

@@ -1,5 +1,6 @@
 #pylint: disable=unused-argument
 from __future__ import annotations
+from dataclasses import asdict
 from typing import TYPE_CHECKING
 from allocation.adapters import email, redis_eventpublisher
 from allocation.domain import commands, events, model
@@ -37,6 +38,13 @@ def allocate(
         product.allocate(line)
         uow.commit()
 
+def reallocate(
+        event: events.Deallocated, uow: unit_of_work.AbstractUnitOfWork
+):
+    with uow:
+        product = uow.products.get(sku=event.sku)
+        product.events.append(commands.Allocate(**asdict(event)))
+        uow.commit()
 
 def change_batch_quantity(
         cmd: commands.ChangeBatchQuantity, uow: unit_of_work.AbstractUnitOfWork
@@ -74,3 +82,14 @@ def add_allocation_to_read_model(
             dict(orderid=event.orderid, sku=event.sku, batchref=event.batchref)
         )
         uow.commit()
+
+def remove_allocation_from_read_model(
+        event: events.Deallocated, uow: unit_of_work.SqlAlchemyUnitOfWork,
+):
+    with uow:
+        uow.session.execute(
+            'DELETE FROM allocations_view '
+            ' WHERE orderid = :orderid AND sku = :sku',
+            dict(orderid=event.orderid, sku=event.sku)
+        )
+        uow.commit()

src/allocation/service_layer/messagebus.py

@@ -60,6 +60,10 @@ def handle_command(
         handlers.publish_allocated_event,
         handlers.add_allocation_to_read_model
     ],
+    events.Deallocated: [
+        handlers.remove_allocation_from_read_model,
+        handlers.reallocate,
+    ],
     events.OutOfStock: [handlers.send_out_of_stock_notification],
 }  # type: Dict[Type[events.Event], List[Callable]]
 

tests/integration/test_views.py

@@ -19,3 +19,15 @@ def test_allocations_view(sqlite_session_factory):
         {'sku': 'sku1', 'batchref': 'sku1batch'},
         {'sku': 'sku2', 'batchref': 'sku2batch'},
     ]
+
+
+def test_deallocation(sqlite_session_factory):
+    uow = unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory)
+    messagebus.handle(commands.CreateBatch('b1', 'sku1', 50, None), uow)
+    messagebus.handle(commands.CreateBatch('b2', 'sku1', 50, date.today()), uow)
+    messagebus.handle(commands.Allocate('o1', 'sku1', 40), uow)
+    messagebus.handle(commands.ChangeBatchQuantity('b1', 10), uow)
+
+    assert views.allocations('o1', uow) == [
+        {'sku': 'sku1', 'batchref': 'b2'},
+    ]