streamtest

import StreamTest from 'streamtest'; import { Transform } from 'stream'; import assert from 'assert'; describe('My Stream Lib', () => { it('should capture text output from a stream', async () => { // A simple passthrough stream, representing your stream-under-test const myTestedStream = new Transform({ transform(chunk, encoding, callback) { this.push(chunk.toString().toUpperCase()); // Example transformation callback(); } }); const [outputStream, resultPromise] = StreamTest.toText(); // Create a readable stream from an array of chunks, // pipe it through your tested stream, then into streamtest's collecting stream. StreamTest.fromChunks(['hello ', 'world', '!']) .pipe(myTestedStream) .pipe(outputStream); // Await the collected text and assert against the expected output. assert.equal(await resultPromise, 'HELLO WORLD!'); }); it('should create a stream from objects and collect processed objects', async () => { const [objectOutputStream, objectResultPromise] = StreamTest.toObjects(); const myObjectStream = new Transform({ objectMode: true, transform(obj, encoding, callback) { this.push({ ...obj, processed: true, timestamp: Date.now() }); callback(); } }); StreamTest.fromObjects([{ id: 1, value: 'A' }, { id: 2, value: 'B' }]) .pipe(myObjectStream) .pipe(objectOutputStream); const expected = [ { id: 1, value: 'A', processed: true, timestamp: (await objectResultPromise)[0].timestamp }, { id: 2, value: 'B', processed: true, timestamp: (await objectResultPromise)[1].timestamp } ]; assert.deepStrictEqual(await objectResultPromise, expected); }); });