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How to use streamToString method in Playwright Internal

Best JavaScript code snippet using playwright-internal

streamTransform.test.js

1import { Readable } from 'stream';2import transformStream from './streamTransform';3function streamToString(stream) {4  const chunks = [];5  return new Promise((resolve, reject) => {6    stream.on('data', (chunk) => chunks.push(chunk));7    stream.on('error', reject);8    stream.on('end', () => resolve(Buffer.concat(chunks).toString()));9  });10}11describe('index', () => {12  describe('transformStream()', () => {13    let inputStream;14    let transformedStream;15    let values;16    let expectedResult;17    let count;18    let onMessage;19    beforeEach(() => {20      count = 0;21      values = [22        { value: 1, type: 'begin' },23        { value: 2, type: 'hit' },24        { value: 3, type: 'hit' },25        { value: 4, type: 'end' }26      ];27      expectedResult = [28        JSON.stringify({ value: 2, type: 'begin' }),29        JSON.stringify({ value: 4, type: 'hit' }),30        JSON.stringify({ value: 6, type: 'hit' }),31        JSON.stringify({ value: 8, type: 'end' })32      ]33        .join('\n')34        .concat('\n');35      onMessage = async (message) => ({36        ...message,37        value: message.value * 238      });39    });40    describe('When transform operation receives no chunk', () => {41      beforeEach(() => {42        inputStream = new Readable({43          read() {44            this.push(null);45          }46        });47        transformedStream = transformStream({48          stream: inputStream,49          onMessage50        });51      });52      it('should return correct transformed stream', async () => {53        const buffer = await streamToString(transformedStream);54        expect(buffer).toBe('');55      });56    });57    describe('When transform operation receives normal chunk', () => {58      beforeEach(() => {59        inputStream = new Readable({60          read() {61            this.push(JSON.stringify(values[count]));62            count += 1;63            if (count === values.length) {64              this.push(null);65            }66          }67        });68        transformedStream = transformStream({69          stream: inputStream,70          onMessage71        });72      });73      it('should return correct transformed stream', async () => {74        const buffer = await streamToString(transformedStream);75        expect(buffer).toBe(expectedResult);76      });77    });78    describe('When input stream has multiple newlines in chunk', () => {79      beforeEach(() => {80        inputStream = new Readable({81          read() {82            this.push(`${JSON.stringify(values[count])}\n\n\n`);83            count += 1;84            if (count === values.length) {85              this.push(null);86            }87          }88        });89        transformedStream = transformStream({90          stream: inputStream,91          onMessage92        });93      });94      it('should return correct transformed stream', async () => {95        const buffer = await streamToString(transformedStream);96        expect(buffer).toBe(expectedResult);97      });98    });99    describe('When input stream has newline between chunk', () => {100      beforeEach(() => {101        inputStream = new Readable({102          read() {103            const chunks = `${JSON.stringify(values[count])}`.split(',');104            this.push(chunks[0]);105            this.push(`,${chunks[1]}\n`);106            count += 1;107            if (count === values.length) {108              this.push(null);109            }110          }111        });112        transformedStream = transformStream({113          stream: inputStream,114          onMessage115        });116      });117      it('should return correct transformed stream', async () => {118        const buffer = await streamToString(transformedStream);119        expect(buffer).toBe(expectedResult);120      });121    });122    describe('When input stream has non JSON object between chunks', () => {123      const nonJSONObject = '-,a.';124      beforeEach(() => {125        inputStream = new Readable({126          read() {127            this.push(`${nonJSONObject}\n`);128            this.push(JSON.stringify(values[count]));129            count += 1;130            if (count === values.length) {131              this.push(null);132            }133          }134        });135        transformedStream = transformStream({136          stream: inputStream,137          onMessage138        });139      });140      it('should return correct transformed stream and filter non parse objects', async () => {141        const buffer = await streamToString(transformedStream);142        expect(buffer).toBe(expectedResult);143      });144    });145    describe('When input stream has an error to transform one chunk', () => {146      let onFailure;147      beforeEach(() => {148        inputStream = new Readable({149          read() {150            this.push(JSON.stringify(values[count]));151            count += 1;152            if (count === values.length) {153              this.push(null);154            }155          }156        });157        onMessage = async (message) => {158          if (message.value <= 2) {159            throw new Error('error');160          }161          return {162            ...message,163            value: message.value * 2164          };165        };166        onFailure = jest.fn();167        transformedStream = transformStream({168          stream: inputStream,169          onMessage,170          onFailure171        });172        expectedResult = [173          JSON.stringify({ value: 1, type: 'begin' }),174          JSON.stringify({ value: 2, type: 'hit' }),175          JSON.stringify({ value: 6, type: 'hit' }),176          JSON.stringify({ value: 8, type: 'end' })177        ]178          .join('\n')179          .concat('\n');180      });181      it('should return correct stream with no change in the first two chunk', async () => {182        const buffer = await streamToString(transformedStream);183        expect(buffer).toBe(expectedResult);184        expect(onFailure).toHaveBeenCalledTimes(2);185        const firstCall = onFailure.mock.calls[0];186        const secondCall = onFailure.mock.calls[1];187        expect(firstCall[0].message).toBe('error');188        expect(firstCall[1]).toStrictEqual({189          value: 1,190          type: 'begin'191        });192        expect(secondCall[0].message).toBe('error');193        expect(secondCall[1]).toStrictEqual({194          value: 2,195          type: 'hit'196        });...

test.spec.js

Source: test.spec.js

...77})78describe('vuetify preset', function () {79  it('should work if there is no semver tag', async () => {80    preparing(1)81    const changelog = await streamToString(82      conventionalChangelogCore({ config: preset })83    )84    expect(changelog).toMatchSnapshot()85  })86  it('should replace #[0-9]+ with GitHub issue URL', async () => {87    preparing(2)88    const changelog = await streamToString(89      conventionalChangelogCore({ config: preset })90    )91    expect(changelog).toMatchSnapshot()92  })93  it('should remove the issues that already appear in the subject', async () => {94    preparing(3)95    const changelog = await streamToString(96      conventionalChangelogCore({ config: preset })97    )98    expect(changelog).toMatchSnapshot()99  })100  it('should replace @username with GitHub user URL', async () => {101    preparing(4)102    const changelog = await streamToString(103      conventionalChangelogCore({ config: preset })104    )105    expect(changelog).toMatchSnapshot()106  })107  it('should not discard commit if there is BREAKING CHANGE', async () => {108    preparing(5)109    const changelog = await streamToString(110      conventionalChangelogCore({ config: preset })111    )112    expect(changelog).toMatchSnapshot()113  })114  it('should work if there is a semver tag', async () => {115    preparing(6)116    const changelog = await streamToString(117      conventionalChangelogCore({118        config: preset,119        outputUnreleased: true,120      })121    )122    expect(changelog).to.include('some more features')123    expect(changelog).to.not.include('BREAKING')124  })125  it('should only replace with link to user if it is an username', async () => {126    preparing(7)127    const changelog = await streamToString(128      conventionalChangelogCore({ config: preset })129    )130    expect(changelog).toMatchSnapshot()131  })132  it('parses both default (Revert "<subject>") and custom (revert: <subject>) revert commits', async () => {133    preparing(8)134    const changelog = await streamToString(135      conventionalChangelogCore({ config: preset })136    )137    expect(changelog).toMatchSnapshot()138  })...

test-streamprofile.js

Source: test-streamprofile.js

...97      'confidence',98    ];99    assert.doesNotThrow(() => {100      for (let i = rs2.stream.STREAM_ANY; i < rs2.stream.STREAM_COUNT; i++) {101        let res = rs2.stream.streamToString(i);102        assert.equal(res, streams[i]);103      }104    });105  });106  it('Testing method streamToString - with two arguments', () => {107    assert.throws(() => {108      rs2.stream.streamToString(1, 1);109    });110  });111  it('Testing method streamToString - without argument', () => {112    assert.throws(() => {113      rs2.stream.streamToString();114    });115  });116  it('Testing method streamToString - with stream string', () => {117    const streams = [118      'stream_any',119      'stream_depth',120      'stream_color',121      'stream_infrared',122      'stream_fisheye',123      'stream_gyro',124      'stream_accel',125      'stream_gpio',126      'stream_pose',127      'stream_confidence',128    ];129    streams.forEach((s) => {130      assert.doesNotThrow(() => {131        rs2.stream.streamToString(rs2.stream[s]);132      });133    });134  });...

index.test.ts

Source: index.test.ts

...6describe('streamTag', () => {7  it('handles strings-only correctly', () => {8    const stream = streamTag`test`;910    return streamToString(stream).then(string => {11      expect(string).toBe('test');12    });13  });1415  it('handles empty templates correctly', () => {16    const stream = streamTag``;1718    return streamToString(stream).then(string => {19      expect(string).toBe('');20    });21  });2223  it('handles falsy templates correctly', () => {24    const stream = streamTag`${undefined}${null}${false}`;2526    return streamToString(stream).then(string => {27      expect(string).toBe('');28    });29  });3031  it('handles string interpolations correctly', () => {32    const stream = streamTag`test${'test'}`;3334    return streamToString(stream).then(string => {35      expect(string).toBe('testtest');36    });37  });3839  it('handles number interpolations correctly', () => {40    const stream = streamTag`${0}test${9}`;4142    return streamToString(stream).then(string => {43      expect(string).toBe('0test9');44    });45  });4647  it('handles promise interpolations correctly', () => {48    const stream = streamTag`x${Promise.resolve('test')}x`;4950    return streamToString(stream).then(string => {51      expect(string).toBe('xtestx');52    });53  });5455  it('handles nested streams correctly', () => {56    const stream = streamTag`x${streamTag`test`}x`;5758    return streamToString(stream).then(string => {59      expect(string).toBe('xtestx');60    });61  });6263  it('handles Buffers correctly', () => {64    const stream = streamTag`x${Buffer.from('test')}x`;6566    return streamToString(stream).then(string => {67      expect(string).toBe('xtestx');68    });69  });7071  it('handles deferred interolations correctly', () => {72    const stream = streamTag`73      ${() => 'test'}74      ${() => Buffer.from('test')}75      ${() => Promise.resolve('test')}76      ${() => streamTag`test`}77    `;7879    const output = `80      test81      test82      test83      test84    `8586    return streamToString(stream).then(string => {87      expect(string).toBe(output);88    });89  });9091  describe('React SSR Integration', () => {92    it('correctly interpolates renderToNodeStream', () => {93      const tree = createElement('div', { className: 'test' }, (94        createElement('h1', {}, 'Hello World!')95      ));9697      const stream = streamTag`98        <html>99          <body>100            ${renderToNodeStream(tree)}101          </body>102        </html>103      `;104105      return streamToString(stream).then(string => {106        expect(string).toMatchSnapshot();107      });108    });109  });
...

types.js

Source: types.js

2const assert = require('assert')3const { streamToString } = require('../utils')4const render = require('../lib')5test('regular template string', async () => {6  const result = await streamToString(render`test`)7  assert.strictEqual(result, 'test')8  expect(result).toMatchSnapshot()9})10test('a sync promise', async () => {11  const result = await streamToString(render`1${Promise.resolve('2')}3`)12  assert.strictEqual(result, '123')13  expect(result).toMatchSnapshot()14})15test('an async promise', async () => {16  const promise1 = new Promise(resolve => setImmediate(() => resolve('asdf')))17  const promise2 = new Promise(resolve => setImmediate(() => resolve('1234')))18  const result = await streamToString(render`__1__${promise1}__2__${promise2}__3__`)19  assert.strictEqual(result, '__1__asdf__2__1234__3__')20  expect(result).toMatchSnapshot()21})22test('a promise-returning function', async () => {23  const fn = () => new Promise(resolve => setImmediate(() => resolve('asdf')))24  const result = await streamToString(render`__1__${fn}__2__`)25  assert.strictEqual(result, '__1__asdf__2__')26  expect(result).toMatchSnapshot()27})28test('an async function', async () => {29  const fn = async () => {30    await new Promise(resolve => setImmediate(resolve))31    return 'asdf'32  }33  const result = await streamToString(render`__1__${fn}__2__`)34  assert.strictEqual(result, '__1__asdf__2__')35  expect(result).toMatchSnapshot()36})37test('a stream', async () => {38  const stream = new PassThrough()39  stream.write('asdf')40  stream.end()41  const result = await streamToString(render`__1__${stream}__2__`)42  assert.strictEqual(result, '__1__asdf__2__')43  expect(result).toMatchSnapshot()...

kube.js

Source: kube.js

...8async function getKubeVersion() {9    try {10        const versionCmd = spawn(KUBECTL, K_VERSION);11        versionCmd.on('error', () => exitWithError(NO_KUBECTL_ERROR));12        return (await streamToString(versionCmd.stdout)).split('v')[1].trim();13    } catch(e) {14        exitWithError(NO_KUBECTL_ERROR);15    }16}17async function getNamespaces() {18    const cmd = spawn(KUBECTL, K_GET_NS);19    const output = JSON.parse(await streamToString(cmd.stdout));20    return output.items.map(n => n.metadata.name);21}22async function getServices(namespace) {23    const cmd = spawn(KUBECTL, K_GET_SVC(namespace));24    const output = JSON.parse(await streamToString(cmd.stdout));25    return output.items.map(n => n.metadata.name);26}27async function getPorts(namespace, service) {28    const cmd = spawn(KUBECTL, `-n=${namespace} get svc ${service} -ojson`.split(' '));29    const output = JSON.parse(await streamToString(cmd.stdout));30    return output.spec.ports.map(p => p.port);31}32function portForward({ namespace, service, localPort, targetPort }) {33    return spawn(KUBECTL, `port-forward -n=${namespace} svc/${service} ${localPort}:${targetPort}`.split(' '));34}...

streamToString.test.ts

Source: streamToString.test.ts

1import { ReadStream } from 'fs';2import { streamToString } from '@/util/streamToString';3describe('streamToString', () => {4    test('streamToString(stream)', async () => {5        const buf = Buffer.from('HOGE');6        const stream = ReadStream.from(buf) as ReadStream;7        await expect(streamToString(stream)).resolves.toBe('HOGE');8    });9    test('streamToString(stream) invalid data', async () => {10        const buf = Buffer.from([]);11        const stream = ReadStream.from(buf) as ReadStream;12        await expect(streamToString(stream)).rejects.toThrow();13    });...

Using AI Code Generation

1const { streamToString } = require('@playwright/test/lib/utils/utils');2const { chromium } = require('playwright');3(async () => {4  const browser = await chromium.launch();5  const context = await browser.newContext();6  const page = await context.newPage();7  const element = await page.$('body');8  const stream = await element.screenshotStream();9  const screenshot = await streamToString(stream);10  console.log(screenshot);11  await browser.close();12})();13const { streamToString } = require('@playwright/test/lib/utils/utils');14module.exports = {15};16And in my test file, I have imported this method from utils.js17const { chromium } = require('playwright');18const { streamToString } = require('./utils');19(async () => {20  const browser = await chromium.launch();21  const context = await browser.newContext();22  const page = await context.newPage();23  const element = await page.$('body');24  const stream = await element.screenshotStream();25  const screenshot = await streamToString(stream);26  console.log(screenshot);27  await browser.close();28})();

Using AI Code Generation

1const { streamToString } = require('playwright/lib/utils/utils');2const fs = require('fs');3const path = require('path');4const { chromium } = require('playwright');5(async () => {6  const browser = await chromium.launch();7  const context = await browser.newContext();8  const page = await context.newPage();9  const screenshot = await page.screenshot();10  const data = await streamToString(screenshot);11  fs.writeFileSync(path.join(__dirname, 'google.png'), data);12  await browser.close();13})();14const { Readable } = require('stream');15const { helper } = require('./helper');16module.exports.streamToString = async stream => {17  if (stream instanceof Readable)18    return await helper.readStream(stream);19  return stream.toString();20};21const { Readable } = require('stream');22module.exports.helper = {23  readStream: stream => new Promise((fulfill, reject) => {24    let data = '';25    stream.on('data', chunk => data += chunk);26    stream.on('end', () => fulfill(data));27    stream.on('error', reject);28  }),29};

Using AI Code Generation

1const { streamToString } = require('playwright/lib/utils/utils');2const fs = require('fs');3const path = require('path');4const { chromium } = require('playwright');5(async () => {6  const browser = await chromium.launch();7  const context = await browser.newContext();8  const page = await context.newPage();9  const screenshot = await page.screenshot({ fullPage: true });10  const screenshotPath = path.join(__dirname, 'screenshot.png');11  const fileHandle = await fs.promises.open(screenshotPath, 'w');12  await fileHandle.write(await streamToString(screenshot));13  await fileHandle.close();14  await browser.close();15})();16const { streamToString } = require('playwright/lib/utils/utils');17const fs = require('fs');18const path = require('path');19const { chromium } = require('playwright');20(async () => {21  const browser = await chromium.launch();22  const context = await browser.newContext();23  const page = await context.newPage();24  const screenshot = await page.screenshot({ fullPage: true });25  const screenshotPath = path.join(__dirname, 'screenshot.png');26  const fileHandle = await fs.promises.open(screenshotPath, 'w');27  await fileHandle.write(await streamToString(screenshot));28  await fileHandle.close();29  await browser.close();30})();31const { streamToString } = require('playwright/lib/utils/utils');32const fs = require('fs');33const path = require('path');34const { chromium } = require('playwright');35(async () => {36  const browser = await chromium.launch();37  const context = await browser.newContext();38  const page = await context.newPage();39  const screenshot = await page.screenshot({ fullPage: true });40  const screenshotPath = path.join(__dirname, 'screenshot.png');41  const fileHandle = await fs.promises.open(screenshotPath, 'w');42  await fileHandle.write(await streamToString(screenshot));43  await fileHandle.close();44  await browser.close();45})();

Using AI Code Generation

1const { chromium } = require('playwright');2(async () => {3  const browser = await chromium.launch();4  const page = await browser.newPage();5  const html = await page.evaluate(() => document.documentElement.outerHTML);6  const stream = await page.evaluateHandle(() => document.documentElement);7  const string = await stream.evaluate((node) => {8    const stream = new node.ownerDocument.defaultView.ReadableStream({9      start(controller) {10        const encoder = new TextEncoder();11        const text = node.outerHTML;12        const buffer = encoder.encode(text);13        controller.enqueue(buffer);14        controller.close();15      }16    });17    const reader = stream.getReader();18    const decoder = new TextDecoder();19    let result = '';20    return pump();21    function pump() {22      return reader.read().then(({done, value}) => {23        if (done)24          return result;25        result += decoder.decode(value);26        return pump();27      });28    }29  });30  console.log(string === html);31  await browser.close();32})();33const { chromium } = require('playwright');34(async () => {35  const browser = await chromium.launch();36  const page = await browser.newPage();37  const html = await page.evaluate(() => document.documentElement.outerHTML);38  const stream = await page.evaluateHandle(() => document.documentElement);39  const string = await stream.evaluate((node) => {40    const stream = new node.ownerDocument.defaultView.ReadableStream({41      start(controller) {42        const encoder = new TextEncoder();43        const text = node.outerHTML;44        const buffer = encoder.encode(text);45        controller.enqueue(buffer);46        controller.close();47      }48    });49    const reader = stream.getReader();50    const decoder = new TextDecoder();51    let result = '';52    return pump();53    function pump() {54      return reader.read().then(({done, value}) => {55        if (done)56          return result;57        result += decoder.decode(value);58        return pump();59      });60    }61  });62  console.log(string === html);63  await browser.close();64})();65const { chromium } = require('playwright');66(async () => {

Using AI Code Generation

1const { streamToString } = require('playwright/lib/utils/utils');2const fs = require('fs');3(async () => {4  const file = fs.createReadStream('test.txt');5  const content = await streamToString(file);6  console.log(content);7})();8const { streamToString } = require('playwright/lib/utils/utils');9const fs = require('fs');10(async () => {11  const file = fs.createReadStream('test.txt');12  const content = await streamToString(file);13  console.log(content);14})();15const { streamToString } = require('playwright/lib/utils/utils');16const fs = require('fs');17(async () => {18  const file = fs.createReadStream('test.txt');19  const content = await streamToString(file);20  console.log(content);21})();22const { streamToString } = require('playwright/lib/utils/utils');23const fs = require('fs');24(async () => {25  const file = fs.createReadStream('test.txt');26  const content = await streamToString(file);27  console.log(content);28})();29const { streamToString } = require('playwright/lib/utils/utils');30const fs = require('fs');31(async () => {32  const file = fs.createReadStream('test.txt');33  const content = await streamToString(file);34  console.log(content);35})();36const { streamToString } = require('playwright/lib/utils/utils');37const fs = require('fs');38(async () => {39  const file = fs.createReadStream('test.txt');40  const content = await streamToString(file);41  console.log(content);42})();43const { streamToString } = require('playwright/lib/utils/utils');44const fs = require('fs');45(async () => {

Using AI Code Generation

1const { streamToString } = require('playwright');2const stream = require('stream');3const { Readable } = stream;4const readable = new Readable();5readable.push('hello world');6readable.push(null);7const string = await streamToString(readable);8console.log(string);

StackOverFlow community discussions

Questions

Discussion

firefox browser does not start in playwright

How to run a list of test suites in a single file concurrently in jest?

firefox browser does not start in playwright

Running Playwright in Azure Function

Is it possible to get the selector from a locator object in playwright?

Jest + Playwright - Test callbacks of event-based DOM library

I found the error. It was because of some missing libraries need. I discovered this when I downgraded playwright to version 1.9 and ran the the code then this was the error msg:

(node:12876) UnhandledPromiseRejectionWarning: browserType.launch: Host system is missing dependencies!

Some of the Universal C Runtime files cannot be found on the system. You can fix
that by installing Microsoft Visual C++ Redistributable for Visual Studio from:
https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

Full list of missing libraries:
    vcruntime140.dll
    msvcp140.dll
Error
    at Object.captureStackTrace (D:\Projects\snkrs-play\node_modules\playwright\lib\utils\stackTrace.js:48:19)
    at Connection.sendMessageToServer (D:\Projects\snkrs-play\node_modules\playwright\lib\client\connection.js:69:48)
    at Proxy.<anonymous> (D:\Projects\snkrs-play\node_modules\playwright\lib\client\channelOwner.js:64:61)
    at D:\Projects\snkrs-play\node_modules\playwright\lib\client\browserType.js:64:67
    at BrowserType._wrapApiCall (D:\Projects\snkrs-play\node_modules\playwright\lib\client\channelOwner.js:77:34)
    at BrowserType.launch (D:\Projects\snkrs-play\node_modules\playwright\lib\client\browserType.js:55:21)
    at D:\Projects\snkrs-play\index.js:4:35
    at Object.<anonymous> (D:\Projects\snkrs-play\index.js:7:3)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:12876) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:12876) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

A list of missing libraries was provided. After successful installments, firefox ran fine. I upgraded again to version 1.10 and firefox still works.

https://stackoverflow.com/questions/66984974/firefox-browser-does-not-start-in-playwright

Assuming you are not running test with the --runinband flag, the simple answer is yes but it depends ????

There is a pretty comprehensive GitHub issue jest#6957 that explains certain cases of when tests are run concurrently or in parallel. But it seems to depend on a lot of edge cases where jest tries its best to determine the fastest way to run the tests given the circumstances.

To my knowledge there is no way to force jest to run in parallel.

Aside

Have you considered using playwright instead of puppeteer with jest? Playwright has their own internally built testing library called @playwright/test that is used in place of jest with a similar API. This library allows for explicitly defining test groups in a single file to run in parallel (i.e. test.describe.parallel) or serially (i.e. test.describe.serial). Or even to run all tests in parallel via a config option.

// parallel
test.describe.parallel('group', () => {
  test('runs in parallel 1', async ({ page }) => {});
  test('runs in parallel 2', async ({ page }) => {});
});

// serial
test.describe.serial('group', () => {
  test('runs first', async ({ page }) => {});
  test('runs second', async ({ page }) => {});
});

https://stackoverflow.com/questions/73497773/how-to-run-a-list-of-test-suites-in-a-single-file-concurrently-in-jest

I found the error. It was because of some missing libraries need. I discovered this when I downgraded playwright to version 1.9 and ran the the code then this was the error msg:

(node:12876) UnhandledPromiseRejectionWarning: browserType.launch: Host system is missing dependencies!

Some of the Universal C Runtime files cannot be found on the system. You can fix
that by installing Microsoft Visual C++ Redistributable for Visual Studio from:
https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

Full list of missing libraries:
    vcruntime140.dll
    msvcp140.dll
Error
    at Object.captureStackTrace (D:\Projects\snkrs-play\node_modules\playwright\lib\utils\stackTrace.js:48:19)
    at Connection.sendMessageToServer (D:\Projects\snkrs-play\node_modules\playwright\lib\client\connection.js:69:48)
    at Proxy.<anonymous> (D:\Projects\snkrs-play\node_modules\playwright\lib\client\channelOwner.js:64:61)
    at D:\Projects\snkrs-play\node_modules\playwright\lib\client\browserType.js:64:67
    at BrowserType._wrapApiCall (D:\Projects\snkrs-play\node_modules\playwright\lib\client\channelOwner.js:77:34)
    at BrowserType.launch (D:\Projects\snkrs-play\node_modules\playwright\lib\client\browserType.js:55:21)
    at D:\Projects\snkrs-play\index.js:4:35
    at Object.<anonymous> (D:\Projects\snkrs-play\index.js:7:3)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:12876) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:12876) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

A list of missing libraries was provided. After successful installments, firefox ran fine. I upgraded again to version 1.10 and firefox still works.

https://stackoverflow.com/questions/66984974/firefox-browser-does-not-start-in-playwright

Well this is one way, but not sure if it will work for all possible locators!.

// Get a selector from a playwright locator
import { Locator } from "@playwright/test";
export function extractSelector(locator: Locator) {
    const selector = locator.toString();
    const parts = selector.split("@");
    if (parts.length !== 2) { throw Error("extractSelector: susupect that this is not a locator"); }
    if (parts[0] !== "Locator") { throw Error("extractSelector: did not find locator"); }
    return parts[1];
}

https://stackoverflow.com/questions/72044959/is-it-possible-to-get-the-selector-from-a-locator-object-in-playwright

This question is quite close to a "need more focus" question. But let's try to give it some focus:

Does Playwright has access to the cPicker object on the page? Does it has access to the window object?

Yes, you can access both cPicker and the window object inside an evaluate call.

Should I trigger the events from the HTML file itself, and in the callbacks, print in the DOM the result, in some dummy-element, and then infer from that dummy element text that the callbacks fired?

Exactly, or you can assign values to a javascript variable:

const cPicker = new ColorPicker({
  onClickOutside(e){
  },
  onInput(color){
    window['color'] = color;
  },
  onChange(color){
    window['result'] = color;
  }
})

And then

it('Should call all callbacks with correct arguments', async() => {
    await page.goto(`http://localhost:5000/tests/visual/basic.html`, {waitUntil:'load'})

    // Wait until the next frame
    await page.evaluate(() => new Promise(requestAnimationFrame))

    // Act
   
    // Assert
    const result = await page.evaluate(() => window['color']);
    // Check the value
})

https://stackoverflow.com/questions/65477895/jest-playwright-test-callbacks-of-event-based-dom-library

Blogs

Check out the latest blogs from LambdaTest on this topic:

How To Refresh Page Using Selenium C# [Complete Tutorial]

When working on web automation with Selenium, I encountered scenarios where I needed to refresh pages from time to time. When does this happen? One scenario is that I needed to refresh the page to check that the data I expected to see was still available even after refreshing. Another possibility is to clear form data without going through each input individually.

The Top 52 Selenium Open Source Projects On GitHub

Selenium, a project hosted by the Apache Software Foundation, is an umbrella open-source project comprising a variety of tools and libraries for test automation. Selenium automation framework enables QA engineers to perform automated web application testing using popular programming languages like Python, Java, JavaScript, C#, Ruby, and PHP.

How To Create Custom Menus with CSS Select

When it comes to UI components, there are two versatile methods that we can use to build it for your website: either we can use prebuilt components from a well-known library or framework, or we can develop our UI components from scratch.

Complete Tutorial On Appium Parallel Testing [With Examples]

In today’s fast-paced world, the primary goal of every business is to release their application or websites to the end users as early as possible. As a result, businesses constantly search for ways to test, measure, and improve their products. With the increase in competition, faster time to market (TTM) has become vital for any business to survive in today’s market. However, one of the possible challenges many business teams face is the release cycle time, which usually gets extended for several reasons.

30 Top Automation Testing Tools In 2022

The sky’s the limit (and even beyond that) when you want to run test automation. Technology has developed so much that you can reduce time and stay more productive than you used to 10 years ago. You needn’t put up with the limitations brought to you by Selenium if that’s your go-to automation testing tool. Instead, you can pick from various test automation frameworks and tools to write effective test cases and run them successfully.

Playwright tutorial

LambdaTest’s Playwright tutorial will give you a broader idea about the Playwright automation framework, its unique features, and use cases with examples to exceed your understanding of Playwright testing. This tutorial will give A to Z guidance, from installing the Playwright framework to some best practices and advanced concepts.

Chapters:

What is Playwright : Playwright is comparatively new but has gained good popularity. Get to know some history of the Playwright with some interesting facts connected with it.
How To Install Playwright : Learn in detail about what basic configuration and dependencies are required for installing Playwright and run a test. Get a step-by-step direction for installing the Playwright automation framework.
Playwright Futuristic Features: Launched in 2020, Playwright gained huge popularity quickly because of some obliging features such as Playwright Test Generator and Inspector, Playwright Reporter, Playwright auto-waiting mechanism and etc. Read up on those features to master Playwright testing.
What is Component Testing: Component testing in Playwright is a unique feature that allows a tester to test a single component of a web application without integrating them with other elements. Learn how to perform Component testing on the Playwright automation framework.
Inputs And Buttons In Playwright: Every website has Input boxes and buttons; learn about testing inputs and buttons with different scenarios and examples.
Functions and Selectors in Playwright: Learn how to launch the Chromium browser with Playwright. Also, gain a better understanding of some important functions like “BrowserContext,” which allows you to run multiple browser sessions, and “newPage” which interacts with a page.
Handling Alerts and Dropdowns in Playwright : Playwright interact with different types of alerts and pop-ups, such as simple, confirmation, and prompt, and different types of dropdowns, such as single selector and multi-selector get your hands-on with handling alerts and dropdown in Playright testing.
Playwright vs Puppeteer: Get to know about the difference between two testing frameworks and how they are different than one another, which browsers they support, and what features they provide.
Run Playwright Tests on LambdaTest: Playwright testing with LambdaTest leverages test performance to the utmost. You can run multiple Playwright tests in Parallel with the LammbdaTest test cloud. Get a step-by-step guide to run your Playwright test on the LambdaTest platform.
Playwright Python Tutorial: Playwright automation framework support all major languages such as Python, JavaScript, TypeScript, .NET and etc. However, there are various advantages to Python end-to-end testing with Playwright because of its versatile utility. Get the hang of Playwright python testing with this chapter.
Playwright End To End Testing Tutorial: Get your hands on with Playwright end-to-end testing and learn to use some exciting features such as TraceViewer, Debugging, Networking, Component testing, Visual testing, and many more.
Playwright Video Tutorial: Watch the video tutorials on Playwright testing from experts and get a consecutive in-depth explanation of Playwright automation testing.