mozilla-central/testing/web-platform/tests/streams/readable-streams/cancel.any.js (file symbol)

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// META: global=window,worker,shadowrealm
// META: script=../resources/test-utils.js
// META: script=../resources/rs-utils.js
'use strict';
promise_test(t => {
const randomSource = new RandomPushSource();
let cancellationFinished = false;
const rs = new ReadableStream({
start(c) {
randomSource.ondata = c.enqueue.bind(c);
randomSource.onend = c.close.bind(c);
randomSource.onerror = c.error.bind(c);
},
pull() {
randomSource.readStart();
},
cancel() {
randomSource.readStop();
return new Promise(resolve => {
t.step_timeout(() => {
cancellationFinished = true;
resolve();
}, 1);
});
}
});
const reader = rs.getReader();
// We call delay multiple times to avoid cancelling too early for the
// source to enqueue at least one chunk.
const cancel = delay(5).then(() => delay(5)).then(() => delay(5)).then(() => {
const cancelPromise = reader.cancel();
assert_false(cancellationFinished, 'cancellation in source should happen later');
return cancelPromise;
});
return readableStreamToArray(rs, reader).then(chunks => {
assert_greater_than(chunks.length, 0, 'at least one chunk should be read');
for (let i = 0; i < chunks.length; i++) {
assert_equals(chunks[i].length, 128, 'chunk ' + i + ' should have 128 bytes');
}
return cancel;
}).then(() => {
assert_true(cancellationFinished, 'it returns a promise that is fulfilled when the cancellation finishes');
});
}, 'ReadableStream cancellation: integration test on an infinite stream derived from a random push source');
test(() => {
let recordedReason;
const rs = new ReadableStream({
cancel(reason) {
recordedReason = reason;
}
});
const passedReason = new Error('Sorry, it just wasn\'t meant to be.');
rs.cancel(passedReason);
assert_equals(recordedReason, passedReason,
'the error passed to the underlying source\'s cancel method should equal the one passed to the stream\'s cancel');
}, 'ReadableStream cancellation: cancel(reason) should pass through the given reason to the underlying source');
promise_test(() => {
const rs = new ReadableStream({
start(c) {
c.enqueue('a');
c.close();
},
cancel() {
assert_unreached('underlying source cancel() should not have been called');
}
});
const reader = rs.getReader();
return rs.cancel().then(() => {
assert_unreached('cancel() should be rejected');
}, e => {
assert_equals(e.name, 'TypeError', 'cancel() should be rejected with a TypeError');
}).then(() => {
return reader.read();
}).then(result => {
assert_object_equals(result, { value: 'a', done: false }, 'read() should still work after the attempted cancel');
return reader.closed;
});
}, 'ReadableStream cancellation: cancel() on a locked stream should fail and not call the underlying source cancel');
promise_test(() => {
let cancelReceived = false;
const cancelReason = new Error('I am tired of this stream, I prefer to cancel it');
const rs = new ReadableStream({
cancel(reason) {
cancelReceived = true;
assert_equals(reason, cancelReason, 'cancellation reason given to the underlying source should be equal to the one passed');
}
});
return rs.cancel(cancelReason).then(() => {
assert_true(cancelReceived);
});
}, 'ReadableStream cancellation: should fulfill promise when cancel callback went fine');
promise_test(() => {
const rs = new ReadableStream({
cancel() {
return 'Hello';
}
});
return rs.cancel().then(v => {
assert_equals(v, undefined, 'cancel() return value should be fulfilled with undefined');
});
}, 'ReadableStream cancellation: returning a value from the underlying source\'s cancel should not affect the fulfillment value of the promise returned by the stream\'s cancel');
promise_test(() => {
const thrownError = new Error('test');
let cancelCalled = false;
const rs = new ReadableStream({
cancel() {
cancelCalled = true;
throw thrownError;
}
});
return rs.cancel('test').then(() => {
assert_unreached('cancel should reject');
}, e => {
assert_true(cancelCalled);
assert_equals(e, thrownError);
});
}, 'ReadableStream cancellation: should reject promise when cancel callback raises an exception');
promise_test(() => {
const cancelReason = new Error('test');
const rs = new ReadableStream({
cancel(error) {
assert_equals(error, cancelReason);
return delay(1);
}
});
return rs.cancel(cancelReason);
}, 'ReadableStream cancellation: if the underlying source\'s cancel method returns a promise, the promise returned by the stream\'s cancel should fulfill when that one does (1)');
promise_test(t => {
let resolveSourceCancelPromise;
let sourceCancelPromiseHasFulfilled = false;
const rs = new ReadableStream({
cancel() {
const sourceCancelPromise = new Promise(resolve => resolveSourceCancelPromise = resolve);
sourceCancelPromise.then(() => {
sourceCancelPromiseHasFulfilled = true;
});
return sourceCancelPromise;
}
});
t.step_timeout(() => resolveSourceCancelPromise('Hello'), 1);
return rs.cancel().then(value => {
assert_true(sourceCancelPromiseHasFulfilled, 'cancel() return value should be fulfilled only after the promise returned by the underlying source\'s cancel');
assert_equals(value, undefined, 'cancel() return value should be fulfilled with undefined');
});
}, 'ReadableStream cancellation: if the underlying source\'s cancel method returns a promise, the promise returned by the stream\'s cancel should fulfill when that one does (2)');
promise_test(t => {
let rejectSourceCancelPromise;
let sourceCancelPromiseHasRejected = false;
const rs = new ReadableStream({
cancel() {
const sourceCancelPromise = new Promise((resolve, reject) => rejectSourceCancelPromise = reject);
sourceCancelPromise.catch(() => {
sourceCancelPromiseHasRejected = true;
});
return sourceCancelPromise;
}
});
const errorInCancel = new Error('Sorry, it just wasn\'t meant to be.');
t.step_timeout(() => rejectSourceCancelPromise(errorInCancel), 1);
return rs.cancel().then(() => {
assert_unreached('cancel() return value should be rejected');
}, r => {
assert_true(sourceCancelPromiseHasRejected, 'cancel() return value should be rejected only after the promise returned by the underlying source\'s cancel');
assert_equals(r, errorInCancel, 'cancel() return value should be rejected with the underlying source\'s rejection reason');
});
}, 'ReadableStream cancellation: if the underlying source\'s cancel method returns a promise, the promise returned by the stream\'s cancel should reject when that one does');
promise_test(() => {
const rs = new ReadableStream({
start() {
return new Promise(() => {});
},
pull() {
assert_unreached('pull should not have been called');
}
});
return Promise.all([rs.cancel(), rs.getReader().closed]);
}, 'ReadableStream cancellation: cancelling before start finishes should prevent pull() from being called');
promise_test(async () => {
const events = [];
const pendingPromise = new Promise(() => {});
const rs = new ReadableStream({
pull() {
events.push('pull');
return pendingPromise;
},
cancel() {
events.push('cancel');
}
});
const reader = rs.getReader();
reader.read().catch(() => {}); // No await.
await delay(0);
await Promise.all([reader.cancel(), reader.closed]);
assert_array_equals(events, ['pull', 'cancel'], 'cancel should have been called');
}, 'ReadableStream cancellation: underlyingSource.cancel() should called, even with pending pull');