Fixed test!

Author: alice-i-cecile

crates/bevy_ecs/src/event.rs

@@ -415,12 +415,14 @@ mod tests {
 
     #[test]
     fn event_system_params() {
-        let world = World::default();
         struct E;
-        fn writes(ew: EventWriter<E>) {
+        let mut world = World::default();
+        world.insert_resource(Events::<E>::default());
+
+        fn writes(mut ew: EventWriter<E>) {
             ew.send(E)
         }
-        fn reads(er: EventReader<E>) {
+        fn reads(mut er: EventReader<E>) {
             er.iter();
         }
         fn consumes(ec: EventConsumer<E>) {
@@ -430,15 +432,15 @@ mod tests {
         let mut stage1 = SystemStage::parallel();
         stage1.add_system(writes.system());
         stage1.add_system(reads.system());
+        stage1.run(&mut world);
 
-        stage1.run(&mut World::default());
         let current_events = world.get_resource::<Events<E>>().unwrap();
         assert!(current_events.events_a.len() == 1);
 
         let mut stage2 = SystemStage::parallel();
         stage2.add_system(consumes.system());
 
-        stage2.run(&mut World::default());
+        stage2.run(&mut world);
         let current_events = world.get_resource::<Events<E>>().unwrap();
         assert!(current_events.events_a.len() == 0);
     }