Diffusion Ant (feature/nursery) Code

ant/tests/test_coro_this.js
ddfe6237cab5feature/nursery

test_coro_this.js
View Options

			// Test that `this` is preserved correctly in coroutine/async contexts

			class Widget {
			constructor(name) {
			this.name = name;
			this._value = 42;
			this._boundMethod = this._boundMethod.bind(this);
			}

			_boundMethod() {
			return this._value;
			}

			unboundMethod() {
			return this._value;
			}

			callBound() {
			return this._boundMethod();
			}

			callUnbound() {
			return this.unboundMethod();
			}
			}

			let passed = 0;
			let failed = 0;

			function test(name, fn) {
			try {
			const result = fn();
			if (result instanceof Promise) {
			result.then(() => {
			console.log(`✓ ${name}`);
			passed++;
			}).catch(e => {
			console.log(`✗ ${name}`);
			console.log(` Error: ${e.message}`);
			failed++;
			});
			} else {
			console.log(`✓ ${name}`);
			passed++;
			}
			} catch (e) {
			console.log(`✗ ${name}`);
			console.log(` Error: ${e.message}`);
			failed++;
			}
			}

			function assertEqual(a, b, msg) {
			if (a !== b) throw new Error(msg \|\| `Expected ${b}, got ${a}`);
			}

			console.log('=== Coroutine/Async this preservation tests ===\n');

			// Sync tests
			console.log('-- Synchronous --');

			test('Direct method call preserves this', () => {
			const w = new Widget('test');
			assertEqual(w.callBound(), 42);
			});

			test('Bound method works', () => {
			const w = new Widget('test');
			assertEqual(w._boundMethod(), 42);
			});

			test('Unbound method via this works', () => {
			const w = new Widget('test');
			assertEqual(w.callUnbound(), 42);
			});

			// Test in callback context
			console.log('\n-- In callback context --');

			test('Method call in setTimeout callback', () => {
			return new Promise((resolve, reject) => {
			const w = new Widget('test');
			setTimeout(() => {
			try {
			assertEqual(w.callBound(), 42);
			resolve();
			} catch (e) {
			reject(e);
			}
			}, 10);
			});
			});

			test('Method call in Promise.then', () => {
			const w = new Widget('test');
			return Promise.resolve().then(() => {
			assertEqual(w.callBound(), 42);
			});
			});

			// Test in event handler context (simulated)
			console.log('\n-- In event handler context --');

			test('Method call from stored handler', () => {
			const w = new Widget('test');
			const handlers = [];

			handlers.push(() => {
			return w.callBound();
			});

			for (const h of handlers) {
			assertEqual(h(), 42);
			}
			});

			test('Bound method passed as callback', () => {
			const w = new Widget('test');
			const fn = w._boundMethod;
			assertEqual(fn(), 42);
			});

			// Test class with stdin-like event pattern
			console.log('\n-- Event emitter pattern --');

			class FakeScreen {
			constructor() {
			this._running = true;
			this._handlers = [];
			this._cleanup = this._cleanup.bind(this);
			}

			_cleanup() {
			if (!this._running) return 'already stopped';
			this._running = false;
			return 'cleaned up';
			}

			onKey(fn) {
			this._handlers.push(fn);
			}

			exit() {
			const result = this._cleanup();
			return result;
			}

			emitKey(key) {
			for (const h of this._handlers) {
			h(key);
			}
			}
			}

			test('Exit method calls _cleanup correctly', () => {
			const screen = new FakeScreen();
			let exitResult = null;

			screen.onKey((key) => {
			if (key === 'q') {
			exitResult = screen.exit();
			}
			});

			screen.emitKey('q');
			assertEqual(exitResult, 'cleaned up');
			});

			// Test with async handler
			console.log('\n-- Async event handlers --');

			test('Exit in async handler', async () => {
			const screen = new FakeScreen();
			let exitResult = null;

			screen.onKey(async (key) => {
			if (key === 'q') {
			await Promise.resolve(); // simulate async work
			exitResult = screen.exit();
			}
			});

			screen.emitKey('q');
			await Promise.resolve();
			await Promise.resolve(); // Give time for async handler
			assertEqual(exitResult, 'cleaned up');
			});

			// Test stdin data event pattern
			console.log('\n-- stdin.on pattern --');

			test('Method call from stdin data handler', () => {
			return new Promise((resolve, reject) => {
			const screen = new FakeScreen();
			let result = null;

			const handler = (chunk) => {
			const str = chunk.toString ? chunk.toString() : chunk;
			if (str === 'q') {
			try {
			result = screen.exit();
			assertEqual(result, 'cleaned up');
			resolve();
			} catch (e) {
			reject(e);
			}
			}
			};

			// Simulate stdin event
			setTimeout(() => handler('q'), 10);
			});
			});

			// Wait for async tests
			setTimeout(() => {
			console.log(`\n=== Results: ${passed} passed, ${failed} failed ===`);
			process.exit(failed > 0 ? 1 : 0);
			}, 200);

Owner Packages

No Owners