Add has_registered_events method to Engine class (#3449)

* Add has_registered_events method to Engine class

* Add tests for has_registered_events method and updated indent issue

* Fix code style formatting with pre-commit hooks

---------

Co-authored-by: vfdev <[email protected]>

Author: JeevanChevula

ignite/engine/engine.py

@@ -249,6 +249,17 @@ class TBPTT_Events(EventEnum):
         # we need to update state attributes associated with new custom events
         self.state._update_attrs()
 
+    def has_registered_events(self, event: Any) -> bool:
+        """Check whether engine has a registered event.
+
+        Args:
+            event: Event to check for registration.
+
+        Returns:
+            bool: True if the event is registered, False otherwise.
+        """
+        return event in self._allowed_events
+
     def _handler_wrapper(self, handler: Callable, event_name: Any, event_filter: Callable) -> Callable:
         # signature of the following wrapper will be inspected during registering to check if engine is necessary
         # we have to build a wrapper with relevant signature : solution is functools.wraps

tests/ignite/engine/test_custom_events.py

@@ -46,6 +46,24 @@ def process_func(engine, batch):
         assert h.called
 
 
+def test_has_registered_events_custom():
+    """Test has_registered_events with custom events."""
+
+    class TestEvents(EventEnum):
+        CUSTOM_EVENT = "custom_event"
+
+    engine = Engine(lambda e, b: None)
+
+    # Custom event not registered yet
+    assert not engine.has_registered_events(TestEvents.CUSTOM_EVENT)
+
+    # Register custom event
+    engine.register_events(TestEvents.CUSTOM_EVENT)
+
+    # Now should return True
+    assert engine.has_registered_events(TestEvents.CUSTOM_EVENT)
+
+
 def test_custom_events_asserts():
     # Dummy engine
     engine = Engine(lambda engine, batch: 0)

tests/ignite/engine/test_engine.py

@@ -1174,6 +1174,18 @@ def update_fn(engine, batch):
 
         assert mem_consumption1 == mem_consumption2
 
+    def test_has_registered_events_builtin(self):
+        """Test has_registered_events with built-in events."""
+        engine = Engine(lambda e, b: None)
+
+        # Built-in events should be registered by default
+        assert engine.has_registered_events(Events.STARTED)
+        assert engine.has_registered_events(Events.COMPLETED)
+        assert engine.has_registered_events(Events.ITERATION_COMPLETED)
+
+        # Non-existent event should return False
+        assert not engine.has_registered_events("non_existent_event")
+
     def test_engine_no_data_asserts(self):
         trainer = Engine(lambda e, b: None)