forked from LeenkxTeam/Kmake
88 lines
3.0 KiB
JavaScript
88 lines
3.0 KiB
JavaScript
// META: global=window,worker,shadowrealm
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'use strict';
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// Due to the limitations of floating-point precision, the calculation of desiredSize sometimes gives different answers
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// than adding up the items in the queue would. It is important that implementations give the same result in these edge
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// cases so that developers do not come to depend on non-standard behaviour. See
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// https://github.com/whatwg/streams/issues/582 and linked issues for further discussion.
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promise_test(() => {
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const writer = setupTestStream();
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const writePromises = [
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writer.write(2),
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writer.write(Number.MAX_SAFE_INTEGER)
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];
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assert_equals(writer.desiredSize, 0 - 2 - Number.MAX_SAFE_INTEGER,
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'desiredSize must be calculated using double-precision floating-point arithmetic (after writing two chunks)');
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return Promise.all(writePromises).then(() => {
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assert_equals(writer.desiredSize, 0, '[[queueTotalSize]] must clamp to 0 if it becomes negative');
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});
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}, 'Floating point arithmetic must manifest near NUMBER.MAX_SAFE_INTEGER (total ends up positive)');
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promise_test(() => {
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const writer = setupTestStream();
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const writePromises = [
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writer.write(1e-16),
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writer.write(1)
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];
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assert_equals(writer.desiredSize, 0 - 1e-16 - 1,
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'desiredSize must be calculated using double-precision floating-point arithmetic (after writing two chunks)');
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return Promise.all(writePromises).then(() => {
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assert_equals(writer.desiredSize, 0, '[[queueTotalSize]] must clamp to 0 if it becomes negative');
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});
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}, 'Floating point arithmetic must manifest near 0 (total ends up positive, but clamped)');
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promise_test(() => {
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const writer = setupTestStream();
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const writePromises = [
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writer.write(1e-16),
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writer.write(1),
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writer.write(2e-16)
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];
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assert_equals(writer.desiredSize, 0 - 1e-16 - 1 - 2e-16,
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'desiredSize must be calculated using double-precision floating-point arithmetic (after writing three chunks)');
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return Promise.all(writePromises).then(() => {
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assert_equals(writer.desiredSize, 0 - 1e-16 - 1 - 2e-16 + 1e-16 + 1 + 2e-16,
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'desiredSize must be calculated using floating-point arithmetic (after the three chunks have finished writing)');
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});
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}, 'Floating point arithmetic must manifest near 0 (total ends up positive, and not clamped)');
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promise_test(() => {
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const writer = setupTestStream();
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const writePromises = [
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writer.write(2e-16),
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writer.write(1)
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];
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assert_equals(writer.desiredSize, 0 - 2e-16 - 1,
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'desiredSize must be calculated using double-precision floating-point arithmetic (after writing two chunks)');
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return Promise.all(writePromises).then(() => {
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assert_equals(writer.desiredSize, 0 - 2e-16 - 1 + 2e-16 + 1,
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'desiredSize must be calculated using floating-point arithmetic (after the two chunks have finished writing)');
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});
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}, 'Floating point arithmetic must manifest near 0 (total ends up zero)');
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function setupTestStream() {
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const strategy = {
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size(x) {
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return x;
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},
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highWaterMark: 0
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};
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const ws = new WritableStream({}, strategy);
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return ws.getWriter();
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}
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