Enable handlers to specify EventHandler type

tfw/internals/event_handling/event_handler.py

@@ -1,5 +1,9 @@
-class EventHandler:
+from .type_id_registry import TypeIdRegistryMixin
+
+
+class EventHandler(TypeIdRegistryMixin):
     _instances = set()
+    _type_id_registry = {}
 
     def __init__(self, connector):
         type(self)._instances.add(self)

tfw/internals/event_handling/event_handler_factory_base.py

@@ -4,7 +4,7 @@ from .event_handler import EventHandler
 
 
 class EventHandlerFactoryBase:
-    def build(self, handler_stub, *, keys=None, event_handler_type=EventHandler):
+    def build(self, handler_stub, *, keys=None, event_handler_type=None):
         builder = EventHandlerBuilder(handler_stub, keys, event_handler_type)
         connector = self._build_connector()
         event_handler = builder.build(connector)
@@ -21,7 +21,13 @@ class EventHandlerFactoryBase:
 class EventHandlerBuilder:
     def __init__(self, event_handler, supplied_keys, event_handler_type):
         self._analyzer = HandlerStubAnalyzer(event_handler, supplied_keys)
-        self._event_handler_type = event_handler_type
+        self._event_handler_type = self._determine_type(event_handler_type)
+
+    def _determine_type(self, provided_type):
+        type_ = provided_type or self._analyzer.event_handler_type or EventHandler
+        if not issubclass(type_, EventHandler):
+            raise ValueError("No type supplied!")
+        return type_
 
     def build(self, connector):
         event_handler = self._event_handler_type(connector)
@@ -66,3 +72,8 @@ class HandlerStubAnalyzer:
     @property
     def cleanup(self):
         return self._event_handler.cleanup
+
+    @property
+    def event_handler_type(self):
+        with suppress(AttributeError):
+            return EventHandler.get_type(self._event_handler.type_id)

tfw/internals/event_handling/test_event_handler.py

@@ -6,6 +6,8 @@ import pytest
 
 from .event_handler_factory_base import EventHandlerFactoryBase
 from .event_handler import EventHandler
+from .control_event_handler import ControlEventHandler
+from .fsm_aware_event_handler import FSMAwareEventHandler
 
 
 class MockEventHandlerFactory(EventHandlerFactoryBase):
@@ -130,6 +132,28 @@ def test_build_from_simple_object(test_keys, test_msg):
     assert msg == test_msg
 
 
+def test_build_type():
+    class SomeControlHandler:
+        keys = ['cica']
+        type_id = 'ControlEventHandler'
+        # pylint: disable=no-self-use
+        def handle_event(self, *_):
+            pass
+
+    eh = MockEventHandlerFactory().build(SomeControlHandler())
+    assert isinstance(eh, ControlEventHandler)
+
+    eh = MockEventHandlerFactory().build(SomeControlHandler(), event_handler_type=EventHandler)
+    assert type(eh) == EventHandler  # pylint: disable=unidiomatic-typecheck
+
+    SomeControlHandler.type_id = 'FSMAwareEventHandler'
+    eh = MockEventHandlerFactory().build(SomeControlHandler())
+    assert isinstance(eh, FSMAwareEventHandler)
+
+    eh = MockEventHandlerFactory().build(lambda *_: None, keys=['cica'])
+    assert isinstance(eh, EventHandler)
+
+
 def test_build_from_callable(test_keys, test_msg):
     mock_eh = MockCallable()