Add a test for the listener bug fixed in #424 (#425)

CHANGELOG.md

@@ -1,3 +1,9 @@
+## [[v0.13.1]](https://github.com/mlange-42/arche/compare/v0.13.0...v0.13.1)
+
+### Bugfixes
+
+* Fixes dispatch listener bug that did not clear component restriction (#424, [g-getsov](https://github.com/g-getsov))
+
 ## [[v0.13.0]](https://github.com/mlange-42/arche/compare/v0.12.0...v0.13.0)
 
 ### Features

listener/dispatch.go

@@ -12,10 +12,10 @@ import (
 //
 // To make it possible for systems to add listeners, Dispatch can be added to the [ecs.World] as a resource.
 type Dispatch struct {
-	listeners     []ecs.Listener
-	events        event.Subscription
-	components    ecs.Mask
-	hasComponents bool
+	listeners     []ecs.Listener     // Sub-listeners to dispatch events to.
+	events        event.Subscription // Subscribed event types.
+	components    ecs.Mask           // Subscribed components.
+	hasComponents bool               // Whether there is a restriction to components.
 }
 
 // NewDispatch returns a new [Dispatch] listener with the given sub-listeners.

listener/dispatch_test.go

@@ -35,12 +35,18 @@ func TestDispatch(t *testing.T) {
 		event.Components,
 		posID,
 	)
+	h3 := EventHandler{}
+	l3 := listener.NewCallback(
+		h3.Notify,
+		event.Entities,
+	)
 
 	ls := listener.NewDispatch(&l1)
 	ls.AddListener(&l2)
 	world.SetListener(&ls)
 
 	assert.Equal(t, event.Entities|event.Components, ls.Subscriptions())
+	assert.NotNil(t, ls.Components())
 
 	world.NewEntity(posID, velID)
 	e := world.NewEntity()
@@ -55,6 +61,11 @@ func TestDispatch(t *testing.T) {
 
 	assert.Equal(t, 1, len(h1.events))
 	assert.Equal(t, 2, len(h2.events))
+
+	ls.AddListener(&l3)
+
+	assert.Equal(t, event.Entities|event.Components, ls.Subscriptions())
+	assert.Nil(t, ls.Components())
 }
 
 func TestDispatchRelations(t *testing.T) {