events: add a few tests

PR-URL: #35806
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: benjamingr

lib/internal/event_target.js

@@ -72,10 +72,10 @@ const isTrusted = ObjectGetOwnPropertyDescriptor({
 },'isTrusted').get;
 
 classEvent{
-constructor(type,options){
+constructor(type,options=null){
 if(arguments.length===0)
 thrownewERR_MISSING_ARGS('type');
-if(options!=null)
+if(options!==null)
 validateObject(options,'options');
 const{ cancelable, bubbles, composed }={ ...options};
 this[kCancelable]=!!cancelable;

test/parallel/test-eventtarget.js

@@ -414,6 +414,7 @@ let asyncTest = Promise.resolve();
 }
 
 {
+// Event Statics
 strictEqual(Event.NONE,0);
 strictEqual(Event.CAPTURING_PHASE,1);
 strictEqual(Event.AT_TARGET,2);
@@ -424,6 +425,8 @@ let asyncTest = Promise.resolve();
 strictEqual(e.eventPhase,Event.AT_TARGET);
 }),{once: true});
 target.dispatchEvent(newEvent('foo'));
+// Event is a function
+strictEqual(Event.length,1);
 }
 
 {
@@ -485,3 +488,32 @@ let asyncTest = Promise.resolve();
 eventTarget.dispatchEvent(event);
 strictEqual(event.target,eventTarget);
 }
+{
+// Event target exported keys
+consteventTarget=newEventTarget();
+deepStrictEqual(Object.keys(eventTarget),[]);
+deepStrictEqual(Object.getOwnPropertyNames(eventTarget),[]);
+constparentKeys=Object.keys(Object.getPrototypeOf(eventTarget)).sort();
+constkeys=['addEventListener','dispatchEvent','removeEventListener'];
+deepStrictEqual(parentKeys,keys);
+}
+{
+// Subclassing
+classSubTargetextendsEventTarget{}
+consttarget=newSubTarget();
+target.addEventListener('foo',common.mustCall());
+target.dispatchEvent(newEvent('foo'));
+}
+{
+// Test event order
+consttarget=newEventTarget();
+letstate=0;
+target.addEventListener('foo',common.mustCall(()=>{
+strictEqual(state,0);
+state++;
+}));
+target.addEventListener('foo',common.mustCall(()=>{
+strictEqual(state,1);
+}));
+target.dispatchEvent(newEvent('foo'));
+}