Diffusion Ant (master) Code

ant/examples/spec/streams-readable.js
dce8e2e6fb90master

streams-readable.js
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			import { test, testDeep, testThrows, summary } from './helpers.js';

			console.log('ReadableStream / DefaultController / DefaultReader Tests\n');

			test('RS typeof', typeof ReadableStream, 'function');
			test('RS toStringTag', Object.prototype.toString.call(new ReadableStream()), '[object ReadableStream]');

			const rs = new ReadableStream();
			test('RS locked initially false', rs.locked, false);

			testThrows('RS requires new', () => ReadableStream());
			testThrows('RS rejects null source', () => new ReadableStream(null));
			testThrows('RS rejects invalid type', () => new ReadableStream({ type: 'invalid' }));
			testThrows('RS rejects null type', () => new ReadableStream({ type: null }));

			const rs2 = new ReadableStream({ type: undefined });
			test('RS accepts undefined type', rs2.locked, false);

			let startCalled = false;
			let startController = null;
			const rs3 = new ReadableStream({
			start(c) { startCalled = true; startController = c; }
			});
			test('start called synchronously', startCalled, true);
			test('controller has desiredSize', startController.desiredSize, 1);
			test('controller toStringTag', Object.prototype.toString.call(startController), '[object ReadableStreamDefaultController]');

			testThrows('controller cannot be constructed', () => new ReadableStreamDefaultController());

			const rs4 = new ReadableStream({
			start(c) { c.enqueue('a'); c.enqueue('b'); c.close(); }
			});

			const reader = rs4.getReader();
			test('locked after getReader', rs4.locked, true);
			test('reader toStringTag', Object.prototype.toString.call(reader), '[object ReadableStreamDefaultReader]');

			testThrows('cannot get second reader', () => rs4.getReader());
			testThrows('getReader rejects unknown mode', () => new ReadableStream().getReader({ mode: 'potato' }));

			async function testReadSequence() {
			const r1 = await reader.read();
			test('read 1 value', r1.value, 'a');
			test('read 1 done', r1.done, false);

			const r2 = await reader.read();
			test('read 2 value', r2.value, 'b');
			test('read 2 done', r2.done, false);

			const r3 = await reader.read();
			test('read 3 done', r3.done, true);
			test('read 3 value', r3.value, undefined);
			}

			async function testClosedPromise() {
			const rs = new ReadableStream({
			start(c) { c.close(); }
			});
			const reader = rs.getReader();
			await reader.closed;
			test('closed resolves on close', true, true);
			}

			async function testCancel() {
			let cancelReason = null;
			const rs = new ReadableStream({
			cancel(reason) { cancelReason = reason; }
			});
			await rs.cancel('test reason');
			test('cancel passes reason', cancelReason, 'test reason');
			}

			async function testPullBackpressure() {
			let pullCount = 0;
			const rs = new ReadableStream({
			pull(c) {
			pullCount++;
			c.enqueue(pullCount);
			}
			}, { highWaterMark: 1 });

			await new Promise(r => setTimeout(r, 50));
			test('pull called once at start', pullCount, 1);

			const reader = rs.getReader();
			const r1 = await reader.read();
			test('pull backpressure value', r1.value, 1);

			await new Promise(r => setTimeout(r, 50));
			test('pull called again after read', pullCount, 2);
			}

			async function testReleaseLock() {
			const rs = new ReadableStream({
			start(c) { c.enqueue('x'); }
			});
			const reader = rs.getReader();
			reader.releaseLock();
			test('locked false after release', rs.locked, false);

			const reader2 = rs.getReader();
			const r = await reader2.read();
			test('new reader can read', r.value, 'x');
			}

			async function testDesiredSize() {
			let ctrl;
			new ReadableStream({
			start(c) {
			ctrl = c;
			}
			});
			await new Promise(r => setTimeout(r, 0));
			test('desiredSize initially 1', ctrl.desiredSize, 1);
			ctrl.enqueue('a');
			test('desiredSize after enqueue', ctrl.desiredSize, 0);
			ctrl.close();
			test('desiredSize after close', ctrl.desiredSize, 0);
			}

			async function testErrorStream() {
			const err = new Error('boom');
			const rs = new ReadableStream({
			start(c) { c.error(err); }
			});
			const reader = rs.getReader();
			try {
			await reader.read();
			test('errored stream should reject read', false, true);
			} catch (e) {
			test('errored stream rejects with error', e, err);
			}
			}

			async function testCustomStrategy() {
			const rs = new ReadableStream({
			start(c) {
			c.enqueue(new Uint8Array(10));
			c.enqueue(new Uint8Array(20));
			}
			}, {
			highWaterMark: 64,
			size(chunk) { return chunk.byteLength; }
			});

			const reader = rs.getReader();
			const r1 = await reader.read();
			test('custom strategy chunk size', r1.value.byteLength, 10);
			}

			async function testSubclass() {
			class MyStream extends ReadableStream {
			myMethod() { return 42; }
			}
			const ms = new MyStream({ start(c) { c.close(); } });
			test('subclass instanceof', ms instanceof ReadableStream, true);
			test('subclass method', ms.myMethod(), 42);
			}

			await testReadSequence();
			await testClosedPromise();
			await testCancel();
			await testPullBackpressure();
			await testReleaseLock();
			await testDesiredSize();
			await testErrorStream();
			await testCustomStrategy();
			await testSubclass();

			summary();

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