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// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
function assertEqualsAsync(expected, run, msg) {
var actual;
var hadValue = false;
var hadError = false;
var promise = run();
if (typeof promise !== "object" || typeof promise.then !== "function") {
throw new MjsUnitAssertionError(
"Expected " + run.toString() +
" to return a Promise, but it returned " + PrettyPrint(promise));
}
promise.then(function(value) { hadValue = true; actual = value; },
function(error) { hadError = true; actual = error; });
assertFalse(hadValue || hadError);
%PerformMicrotaskCheckpoint();
if (hadError) throw actual;
assertTrue(
hadValue, "Expected '" + run.toString() + "' to produce a value");
assertEquals(expected, actual, msg);
};
// Rename a function so that it can help omit things from stack trace.
function test(fn) {
return Object.defineProperty(fn, "name", {
enumerable: false,
configurable: true,
value: "@" + fn.name,
writable: false
});
}
function getStack(error) {
var stack = error.stack.split('\n').
filter(function(line) {
return /^\s*at @?[a-zA-Z0-9_]/.test(line);
}).
map(line =>
line.replace(/^\s*at (@?(?:new )?[a-zA-Z0-9_\.\[\]]+)(.*)/, "$1"));
// remove `Promise.then()` invocation by assertEqualsAsync()
if (stack[2] === "assertEqualsAsync") return [];
return stack.reverse();
}
var log = [];
class FakePromise extends Promise {
constructor(executor) {
var stack = getStack(new Error("Getting Callstack"));
if (stack.length) {
var first = -1;
for (var i = 0; i < stack.length; ++i) {
if (stack[i][0] === '@') {
first = i;
break;
}
}
while (first > 0) stack.shift(), --first;
if (stack.length) {
log.push("@@Species: [" + stack.join(" > ") + "]");
}
}
return new Promise(executor);
}
};
Object.defineProperty(Promise, Symbol.species, {
value: FakePromise,
configurable: true,
enumerable: false,
writable: false
});
// Internal `AsyncFunctionAwait` only --- no @@species invocations.
async function asyncFn() { return await "foo"; }
assertEqualsAsync("foo", test(function testInternalOnly() { return asyncFn(); },
"should not call Promise[@@Species]"));
assertEquals([], log);
log.length = 0;
assertEqualsAsync(
"foo",
test(function testThenOnReturnedPromise() {
return asyncFn().then(x => (log.push("Then: " + x), x));
}),
"should call Promise[@@Species] after non-internal Then");
assertEquals([
"@@Species: [@testThenOnReturnedPromise > Promise.then > new FakePromise]",
"Then: foo"
], log);
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