Merge pull request #3713 from cdr/jsjoeio-test-emitter

feat(test): try calling .dispose() x2 in emitter

test/unit/emitter.test.ts

@@ -41,7 +41,7 @@ describe("emitter", () => {
 
     // Register the onHelloWorld listener
     // and the onGoodbyeWorld
-    emitter.event(onHelloWorld)
+    const _onHelloWorld = emitter.event(onHelloWorld)
     emitter.event(onGoodbyeWorld)
 
     await emitter.emit({ event: HELLO_WORLD, callback: mockCallback })
@@ -56,6 +56,12 @@ describe("emitter", () => {
     expect(mockSecondCallback).toHaveBeenCalled()
     expect(mockSecondCallback).toHaveBeenCalledTimes(1)
 
+    // Dispose of individual listener
+    _onHelloWorld.dispose()
+
+    // Try disposing twice
+    _onHelloWorld.dispose()
+
     // Dispose of all the listeners
     emitter.dispose()
   })