From 764aed89ae7b71bc45bd7b2664d6eda8cdacc143 Mon Sep 17 00:00:00 2001
From: Matthew Penner <me@matthewp.io>
Date: Sat, 22 Jan 2022 10:14:54 -0700
Subject: [PATCH] events: remove waitgroup on Publish, add Destroy test

---
 events/events.go      |  4 ----
 events/events_test.go | 55 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/events/events.go b/events/events.go
index c0d8213..d87a0d7 100644
--- a/events/events.go
+++ b/events/events.go
@@ -104,17 +104,13 @@ func (b *Bus) Publish(topic string, data interface{}) {
 		return
 	}
 
-	var wg sync.WaitGroup
 	event := Event{Topic: topic, Data: data}
 	for _, listener := range listeners {
 		l := listener
-		wg.Add(1)
 		go func(l Listener, event Event) {
-			defer wg.Done()
 			l <- event
 		}(l, event)
 	}
-	wg.Wait()
 }
 
 // Destroy destroys the Event Bus by unregistering and closing all listeners.
diff --git a/events/events_test.go b/events/events_test.go
index 542a8e2..22949d4 100644
--- a/events/events_test.go
+++ b/events/events_test.go
@@ -168,3 +168,58 @@ func TestBus_Publish(t *testing.T) {
 		})
 	})
 }
+
+func TestBus_Destroy(t *testing.T) {
+	g := Goblin(t)
+
+	g.Describe("Destroy", func() {
+		g.It("unsubscribes and closes all listeners", func() {
+			bus := NewBus()
+
+			listener := make(chan Event)
+			bus.On(listener, "test")
+
+			done := make(chan struct{}, 1)
+			go func() {
+				select {
+				case m := <-listener:
+					g.Assert(m).IsZero()
+				case <-time.After(1 * time.Second):
+					g.Fail("listener did not receive message in time")
+				}
+				done <- struct{}{}
+			}()
+			bus.Destroy()
+			<-done
+
+			g.Assert(bus.listeners).Equal(map[string][]Listener{})
+		})
+
+		// This is a check that ensures Destroy only closes each listener
+		// channel once, even if it is subscribed to multiple topics.
+		//
+		// Closing a channel multiple times will cause a runtime panic, which
+		// I'm pretty sure we don't want.
+		g.It("unsubscribes and closes channel only once", func() {
+			bus := NewBus()
+
+			listener := make(chan Event)
+			bus.On(listener, "test", "test2", "test3", "test4", "test5")
+
+			done := make(chan struct{}, 1)
+			go func() {
+				select {
+				case m := <-listener:
+					g.Assert(m).IsZero()
+				case <-time.After(1 * time.Second):
+					g.Fail("listener did not receive message in time")
+				}
+				done <- struct{}{}
+			}()
+			bus.Destroy()
+			<-done
+
+			g.Assert(bus.listeners).Equal(map[string][]Listener{})
+		})
+	})
+}