fix tests

Author: pgorecki

.idea/python-ddd.iml

@@ -19,7 +19,7 @@ repos:
           - --ignore-init-module-imports
 
   - repo: https://github.com/pycqa/isort
-    rev: 5.11.2
+    rev: 5.12.0
     hooks:
       - id: isort
         name: isort (python)

.pre-commit-config.yaml

@@ -12,7 +12,7 @@ class BiddingModule(BusinessModule):
     supported_events = ()
 
     def configure_unit_of_work(self, uow):
-        """Here we have a chance to add extra UOW attributes to be injected into command/query handers"""
+        """Here we have a chance to add extra UOW attributes to be injected into command/query handlers"""
         uow.listing_repository = PostgresJsonListingRepository(
             db_session=uow.db_session
         )

src/modules/bidding/__init__.py

@@ -23,7 +23,7 @@ def __init__(self):
     def add_event_handler(self, event_class: type[Event], event_handler: callable):
         self._handlers[event_class].add(event_handler)
 
-    def dispatch(self, event: type[Event], sender: any = None):
+    def dispatch(self, event: type[Event]):
         event_class = type(event)
         for event_handler in self._handlers[event_class]:
-            event_handler(event, sender)
+            event_handler(event)

src/seedwork/application/event_dispatcher.py

@@ -1,2 +1,6 @@
 class ApplicationException(Exception):
     pass
+
+
+class UnitOfWorkNotSetException(ApplicationException):
+    pass

src/seedwork/application/exceptions.py

@@ -1,4 +1,5 @@
 from seedwork.application.event_dispatcher import EventDispatcher
+from seedwork.application.exceptions import UnitOfWorkNotSetException
 from seedwork.infrastructure.logging import logger
 
 
@@ -110,18 +111,19 @@ def unit_of_work(self, **kwargs):
 
     def create_unit_of_work(self, correlation_id, db_session, kwargs):
         """Unit of Work factory, creates new unit of work"""
-        uow = self.unit_of_work_class(
+        uow_kwargs = dict(
             module=self,
             correlation_id=correlation_id,
             db_session=db_session,
             **self.get_unit_of_work_init_kwargs(),
             **kwargs,
         )
+        uow = self.unit_of_work_class(**uow_kwargs)
         return uow
 
     def get_unit_of_work_init_kwargs(self):
         """Returns additional kwargs used for initialization of new Unit of Work"""
-        return self.init_kwargs
+        return {}
 
     def configure_unit_of_work(self, uow):
         """Allows to alter Unit of Work (i.e. add extra attributes) after it is instantiated"""
@@ -158,7 +160,10 @@ def execute_query(self, query):
     def uow(self) -> UnitOfWork:
         """Get current unit of work. Use self.unit_of_work() to create a new instance of UoW"""
         uow = self._uow.get()
-        assert uow, f"Unit of work not set in {self}, use context manager"
+        if uow is None:
+            raise UnitOfWorkNotSetException(
+                f"Unit of work not set in {self}, use context manager"
+            )
         return uow
 
     def resolve_handler_kwargs(self, kwarg_params) -> dict:
@@ -172,29 +177,14 @@ def resolve_handler_kwargs(self, kwarg_params) -> dict:
 
     def publish_domain_events(self, events):
         for event in events:
-            self._domain_event_dispatcher.dispatch(event=event, sender=self)
+            self._domain_event_dispatcher.dispatch(event=event)
 
-    def handle_domain_event(
-        self, event: type[DomainEvent], sender: type["BusinessModule"]
-    ):
+    def handle_domain_event(self, event: type[DomainEvent]):
         """Execute all registered handlers within this module for this event type"""
-        event_was_sent_by_other_module = self is not sender
-
-        if event_was_sent_by_other_module:
-            # The sender executed the command that resulted in an event being published.
-            # as a rule of thumb we want to handle the domain event within same transaction,
-            # thus within same Unit of Work.
-            # Therefore, the receiver must use UoW of sender
-            original_uow = self._uow.get()
-            self._uow.set(sender.uow)
 
         for handler in self.event_handlers:
             event_class, handler_parameters = self.registry.inspect_handler_parameters(
                 handler
             )
             if event_class is type(event):
                 handler(event, self)
-
-        if event_was_sent_by_other_module:
-            # restore the original UoW
-            self._uow.set(original_uow)

src/seedwork/application/modules.py

@@ -5,7 +5,7 @@
 from seedwork.application.command_handlers import CommandResult
 from seedwork.application.commands import Command
 from seedwork.application.event_dispatcher import InMemoryEventDispatcher
-from seedwork.application.modules import BusinessModule
+from seedwork.application.modules import BusinessModule, UnitOfWork
 from seedwork.application.registry import Registry
 from seedwork.domain.events import DomainEvent
 
@@ -33,7 +33,13 @@ def on_user_created(event: UserCreatedEvent, module: type[BusinessModule]):
     module.on_user_created_fired = True
 
 
+@dataclass
+class CustomUnitOfWork(UnitOfWork):
+    prefix: str
+
+
 class SampleModule(BusinessModule):
+    unit_of_work_class = CustomUnitOfWork
     registry = registry
     supported_commands = (CreateUserCommand,)
     supported_queries = ()

src/seedwork/tests/application/test_module.py

@@ -118,6 +118,9 @@ class MonoModule(BusinessModule):
         when_order_is_shipped_sit_and_relax_policy,
     )
 
+    def get_unit_of_work_init_kwargs(self):
+        return dict(history=self.init_kwargs["history"])
+
 
 @pytest.mark.integration
 def test_mono_module_command_branching_flow():

src/seedwork/tests/application/test_mono_module_branching.py

@@ -108,6 +108,9 @@ class MonoModule(BusinessModule):
         when_order_is_shipped_sit_and_relax_policy,
     )
 
+    def get_unit_of_work_init_kwargs(self):
+        return dict(history=self.init_kwargs["history"])
+
 
 @pytest.mark.integration
 def test_mono_module_command_linear_flow():

src/seedwork/tests/application/test_mono_module_linear.py

@@ -5,6 +5,7 @@
 from seedwork.application.command_handlers import CommandResult
 from seedwork.application.commands import Command
 from seedwork.application.event_dispatcher import InMemoryEventDispatcher
+from seedwork.application.exceptions import UnitOfWorkNotSetException
 from seedwork.application.modules import BusinessModule, UnitOfWork
 from seedwork.application.registry import Registry
 from seedwork.domain.events import DomainEvent
@@ -73,6 +74,9 @@ class PingModule(BusinessModule):
     supported_queries = ()
     event_handlers = (when_pong_received_sit_and_relax_policy,)
 
+    def get_unit_of_work_init_kwargs(self):
+        return dict(history=self.init_kwargs["history"])
+
 
 class PongModule(BusinessModule):
     registry = registry
@@ -83,18 +87,19 @@ class PongModule(BusinessModule):
 
 
 @pytest.mark.integration
-def test_ping_pong_flow():
-    """This tests the linear code flow:
-    CompleteOrderCommand → OrderCompletedEvent → when_order_is_completed_process_payment_policy →
-        → ProcessPaymentCommand → PaymentProcessedEvent → when_payment_is_processed_ship_order_policy →
-            → ShipOrderCommand → OrderShippedEvent → when_order_is_shipped_sit_and_relax_policy
+def test_handing_of_domain_event_across_modules_is_not_possible():
+    """
+    In this scenario, a domain event published by ping module,
+    cannot be handled by pong module, because these modules
+    have separate unit of works. This is by design.
+    If such inter module communication is requires, is should be carried out
+    by integration events.
     """
     history = []
     dispatcher = InMemoryEventDispatcher()
     ping_module = PingModule(domain_event_dispatcher=dispatcher, history=history)
     pong_module = PongModule(domain_event_dispatcher=dispatcher, history=history)
 
-    with ping_module.unit_of_work():
-        ping_module.execute_command(SendPing())
-
-    assert history == ["SendPing", "PingSent", "SendPong", "PongSent"]
+    with pytest.raises(UnitOfWorkNotSetException):
+        with ping_module.unit_of_work():
+            ping_module.execute_command(SendPing())