test: pull html/webappapis/microtask-queuing WPT

With the command:
```
git node wpt html/webappapis/microtask-queuing
```
PR-URL: #25616
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>

Author: joyeecheung

test/fixtures/wpt/README.md

@@ -15,6 +15,7 @@ Last update:
 - url: https://github.com/web-platform-tests/wpt/tree/75b0f336c5/url
 - resources: https://github.com/web-platform-tests/wpt/tree/679a364421/resources
 - interfaces: https://github.com/web-platform-tests/wpt/tree/712c9f275e/interfaces
+- html/webappapis/microtask-queuing: https://github.com/web-platform-tests/wpt/tree/0c3bed38df/html/webappapis/microtask-queuing
 
 [Web Platform Tests]: https://github.com/web-platform-tests/wpt
 [`git node wpt`]: https://github.com/nodejs/node-core-utils/blob/master/docs/git-node.md#git-node-wpt

test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask-exceptions.any.js

@@ -0,0 +1,15 @@
+// META: global=window,worker
+"use strict";
+
+setup({
+allow_uncaught_exception: true
+});
+
+async_test(t=>{
+consterror=newError("boo");
+self.addEventListener("error",t.step_func_done(ev=>{
+assert_equals(ev.error,error);
+}));
+
+queueMicrotask(()=>{throwerror;});
+},"It rethrows exceptions");

test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask.any.js

@@ -0,0 +1,39 @@
+// META: global=window,worker
+"use strict";
+
+test(()=>{
+assert_equals(typeofqueueMicrotask,"function");
+},"It exists and is a function");
+
+test(()=>{
+assert_throws(newTypeError(),()=>queueMicrotask(),"no argument");
+assert_throws(newTypeError(),()=>queueMicrotask(undefined),"undefined");
+assert_throws(newTypeError(),()=>queueMicrotask(null),"null");
+assert_throws(newTypeError(),()=>queueMicrotask(0),"0");
+assert_throws(newTypeError(),()=>queueMicrotask({handleEvent(){}}),"an event handler object");
+assert_throws(newTypeError(),()=>queueMicrotask("window.x = 5;"),"a string");
+},"It throws when given non-functions");
+
+async_test(t=>{
+letcalled=false;
+queueMicrotask(t.step_func_done(()=>{
+called=true;
+}));
+assert_false(called);
+},"It calls the callback asynchronously");
+
+async_test(t=>{
+queueMicrotask(t.step_func_done(function(){// note: intentionally not an arrow function
+assert_array_equals(arguments,[]);
+}),"x","y");
+},"It does not pass any arguments");
+
+async_test(t=>{
+consthappenings=[];
+Promise.resolve().then(()=>happenings.push("a"));
+queueMicrotask(()=>happenings.push("b"));
+Promise.reject().catch(()=>happenings.push("c"));
+queueMicrotask(t.step_func_done(()=>{
+assert_array_equals(happenings,["a","b","c"]);
+}));
+},"It interleaves with promises as expected");

test/fixtures/wpt/html/webappapis/microtask-queuing/queue-microtask.window.js

@@ -0,0 +1,45 @@
+"use strict";
+
+// This does not work as you expect because mutation observer compound microtasks are confusing.
+// Basically you can only use it once per test.
+functionqueueMicrotaskViaMO(cb){
+constobserver=newMutationObserver(cb);
+constnode=document.createTextNode("");
+observer.observe(node,{characterData: true});
+node.data="foo";
+}
+
+// Need to use promise_test to get sequential ordering; otherwise the global mutation observer
+// compound microtask business screws us over.
+
+promise_test(()=>{
+returnnewPromise(resolve=>{
+consthappenings=[];
+
+queueMicrotaskViaMO(()=>happenings.push("x"));
+queueMicrotask(()=>happenings.push("a"));
+
+queueMicrotask(()=>{
+assert_array_equals(happenings,["x","a"]);
+resolve();
+});
+});
+},"It interleaves with MutationObservers as expected");
+
+promise_test(()=>{
+returnnewPromise(resolve=>{
+consthappenings=[];
+
+queueMicrotask(()=>happenings.push("a"));
+Promise.reject().catch(()=>happenings.push("x"));
+queueMicrotaskViaMO(()=>happenings.push(1));
+Promise.resolve().then(()=>happenings.push("y"));
+queueMicrotask(()=>happenings.push("b"));
+queueMicrotask(()=>happenings.push("c"));
+
+queueMicrotask(()=>{
+assert_array_equals(happenings,["a","x",1,"y","b","c"]);
+resolve();
+});
+});
+},"It interleaves with MutationObservers and promises together as expected");

test/fixtures/wpt/versions.json

@@ -18,5 +18,9 @@
 "interfaces": {
 "commit": "712c9f275e83997884749dbcaa503f12c0ff5bba",
 "path": "interfaces"
+ },
+"html/webappapis/microtask-queuing": {
+"commit": "0c3bed38df6d9dcd1441873728fb5c1bb59c92df",
+"path": "html/webappapis/microtask-queuing"
  }
 }