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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /streams/readable-streams/read-task-handling.window.html - WPT Dashboard Interop Dashboard
// META: global=window,worker
'use strict';
function performMicrotaskCheckpoint() {
document.createNodeIterator(document, -1, {
acceptNode() {
return NodeFilter.FILTER_ACCEPT;
}
}).nextNode();
}
test(() => {
// Add a getter for "then" that will incidentally be invoked
// during promise resolution.
Object.prototype.__defineGetter__('then', () => {
// Clean up behind ourselves.
delete Object.prototype.then;
// This promise should (like all promises) be resolved
// asynchronously.
var executed = false;
Promise.resolve().then(_ => { executed = true; });
// This shouldn't run microtasks! They should only run
// after the fetch is resolved.
performMicrotaskCheckpoint();
// The fulfill handler above shouldn't have run yet. If it has run,
// throw to reject this promise and fail the test.
assert_false(executed, "shouldn't have run microtasks yet");
// Otherwise act as if there's no "then" property so the promise
// fulfills and the test passes.
return undefined;
});
const readable = new ReadableStream({
pull(c) {
c.enqueue({});
}
}, { highWaterMark: 0 });
// Create a read request, incidentally resolving a promise with an
// object value, thereby invoking the getter installed above.
readable.getReader().read();
}, "reading from a stream should occur in a microtask scope");