| <!DOCTYPE html> |
| <html> |
| <head> |
| <meta charset="UTF-8"> |
| <title></title> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| </head> |
| <body> |
| <script> |
| function performMicrotaskCheckpoint() { |
| document.createNodeIterator(document, -1, { |
| acceptNode() { |
| return NodeFilter.FILTER_ACCEPT; |
| } |
| }).nextNode(); |
| } |
| |
| promise_test(function() { |
| return fetch("../resources/data.json").then(function(response) { |
| // 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. |
| if (executed) { |
| throw "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; |
| }); |
| |
| // Create a read request, incidentally resolving a promise with an |
| // object value, thereby invoking the getter installed above. |
| return response.body.getReader().read(); |
| }); |
| }, "reading from a body stream should occur in a microtask scope"); |
| </script> |
| </body> |
| </html> |
