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How to use shallowReadonly method in Playwright Internal

Best JavaScript code snippet using playwright-internal

setup.js

...77        const publicPropertiesMap = extend(Object.create(null), {78            $: i => i,79            $el: i => i.vnode.el,80            $data: i => i.data,81            $props: i => ( shallowReadonly(i.props) ),82            $attrs: i => ( shallowReadonly(i.attrs) ),83            $slots: i => ( shallowReadonly(i.slots) ),84            $refs: i => ( shallowReadonly(i.refs) ),85            $parent: i => i.parent && i.parent.proxy,86            $root: i => i.root && i.root.proxy,87            $emit: i => i.emit,88            $options: i => ( resolveMergedOptions(i) ),89            $forceUpdate: i => () => queueJob(i.update),90            $nextTick: () => nextTick,91            $watch: i => ( instanceWatch.bind(i) )92        });93        // In dev mode, the proxy target exposes the same properties as seen on `this`94        // for easier console inspection. In prod mode it will be an empty object so95        // these properties definitions can be skipped.96        function createRenderContext(instance) {97            const target = {};98            // expose internal instance for proxy handlers99            Object.defineProperty(target, `_`, {100                configurable: true,101                enumerable: false,102                get: () => instance103            });104            // expose public properties105            Object.keys(publicPropertiesMap).forEach(key => {106                Object.defineProperty(target, key, {107                    configurable: true,108                    enumerable: false,109                    get: () => publicPropertiesMap[key](instance),110                    // intercepted by the proxy so no need for implementation,111                    // but needed to prevent set errors112                    set: NOOP113                });114            });115            // expose global properties116            const { globalProperties } = instance.appContext.config;117            Object.keys(globalProperties).forEach(key => {118                Object.defineProperty(target, key, {119                    configurable: true,120                    enumerable: false,121                    get: () => globalProperties[key],122                    set: NOOP123                });124            });125            return target;126        }127function setupComponent(instance, isSSR = false) {128    isInSSRComponentSetup = isSSR;129    const { props, children, shapeFlag } = instance.vnode;130    const isStateful = shapeFlag & 4 /* STATEFUL_COMPONENT */;131    initProps(instance, props, isStateful, isSSR);132    initSlots(instance, children);133    const setupResult = isStateful134        ? setupStatefulComponent(instance, isSSR)135        : undefined;136    isInSSRComponentSetup = false;137    return setupResult;138}139function setupStatefulComponent(instance, isSSR) {140    const Component = instance.type;141    {142        if (Component.name) {143            validateComponentName(Component.name, instance.appContext.config);144        }145        if (Component.components) {146            const names = Object.keys(Component.components);147            for (let i = 0; i < names.length; i++) {148                validateComponentName(names[i], instance.appContext.config);149            }150        }151        if (Component.directives) {152            const names = Object.keys(Component.directives);153            for (let i = 0; i < names.length; i++) {154                validateDirectiveName(names[i]);155            }156        }157    }158    // 0. create render proxy property access cache159    instance.accessCache = {};160    // 1. create public instance / render proxy161    // also mark it raw so it's never observed162    instance.proxy = new Proxy(instance.ctx, PublicInstanceProxyHandlers);163    {164        exposePropsOnRenderContext(instance);165    }166    // 2. call setup()167    const { setup } = Component;168    if (setup) {169        const setupContext = (instance.setupContext =170            setup.length > 1 ? createSetupContext(instance) : null);171        currentInstance = instance;172        pauseTracking();173        const setupResult = callWithErrorHandling(setup, instance, 0 /* SETUP_FUNCTION */, [ shallowReadonly(instance.props) , setupContext]);174        resetTracking();175        currentInstance = null;176        if (isPromise(setupResult)) {177            if (isSSR) {178                // return the promise so server-renderer can wait on it179                return setupResult.then((resolvedResult) => {180                    handleSetupResult(instance, resolvedResult);181                });182            }183            else {184                // async setup returned Promise.185                // bail here and wait for re-entry.186                instance.asyncDep = setupResult;187            }188        }189        else {190            handleSetupResult(instance, setupResult);191        }192    }193    else {194        finishComponentSetup(instance);195    }196}197function createSetupContext(instance) {198    {199        // We use getters in dev in case libs like test-utils overwrite instance200        // properties (overwrites should not be done in prod)201        return Object.freeze({202            get attrs() {203                return new Proxy(instance.attrs, attrHandlers);204            },205            get slots() {206                return shallowReadonly(instance.slots);207            },208            get emit() {209                return (event, ...args) => instance.emit(event, ...args);210            }211        });212    }213}214        const attrHandlers = {215            get: (target, key) => {216                {217                    markAttrsAccessed();218                }219                return target[key];220            },...

Reactive.jsx

Source: Reactive.jsx

...177          <div className="code">178            <pre>179              <code>180                {`181  const state = shallowReadonly({182    foo: 1,183    nested: {184      bar: 2185    }186  })187  // æ¹å state æ¬èº«ç property å°å¤±è´¥188  state.foo++189  // ...ä½éç¨äºåµå¥å¯¹è±¡190  isReadonly(state.nested) // false191  state.nested.bar++ // éç¨192                `}193              </code>194            </pre>195          </div>...

手写函数readonly.js

Source: 手写函数readonly.js

1function shallowReadonly(obj) {2    return new Proxy(obj, {3        get(obj, key) {4            return obj[key];5        },6        set(obj, key, value) {7            console.warn(`${key}æ¯åªè¯»çï¼ä¸å¯èµå¼`);8            /*9                shallowReadonly åªè¯» æå³ç åªè½get ä¸è½set10                æä»¥åªéè¦å° set ä»£ç åçè¯å¥ å é¤æ11                å¹¶æ·»å ä¸ä¸ª è¦åæé å³å¯12            */13        }14    })15}16function readonly(obj) {17    /* ä»¥ä¸ä»£ç ä¸º reactive çæºç  */18    if (typeof obj === 'object') {19        if (obj instanceof Array) {20            // å¦ææ¯æ°ç»ï¼éåå¤ææ¯ä¸ªåç´ æ¯å¦æ¯å¯¹è±¡21            // å¦æåç´ ä¹æ¯å¯¹è±¡ï¼å ä¹éè¦åè£22            obj.forEach((item, index) => {23                if (typeof item === 'object') {24                    obj[index] = readonly(item)25                }26            })27        } else {28            // å¦ææ¯ä¸ä¸ªå¯¹è±¡ï¼åååºå¯¹è±¡å±æ§çåå¼29            // å¤æåå¼æ¯å¦åæ¯ä¸ä¸ªå¯¹è±¡ï¼å¦ææ¯ï¼ä¹éè¦åè£30            for (let key in obj) {31                let item = obj[key]32                if (typeof item === 'object') {33                    obj[key] = readonly(item)34                }35            }36        }37        return new Proxy(obj, {38            get(obj, key) {39                return obj[key];40            },41            set(obj, key, value) {42                console.warn(`${key}æ¯åªè¯»çï¼ä¸å¯èµå¼`);43                /*44                    shallowReadonly åªè¯» æå³ç åªè½get ä¸è½set45                    æä»¥åªéè¦å° set ä»£ç åçè¯å¥ å é¤æ46                    å¹¶æ·»å ä¸ä¸ª è¦åæé å³å¯47                */48            }49        })50    } else {51        console.warn(`${obj} is not a object`);52    }53}54let object = {55    name: 1,56    id: 2,57    attr: {58        height:359    }60}61let state1 = shallowReadonly(object);62console.log(object,'object-origin');63state1.name = 'name';64state1.attr.height = 'height'65/* nameæ¯åªè¯»çï¼ä¸å¯èµå¼ */66/* ä¸ä¼æ£æµå° height æ¹å */67/* shallowReadonly ç¨äºåå»ºä¸ä¸ªåªè¯»åç´ ï¼åå¹¶ä¸æ¯éå½åªè¯»ï¼åªæç¬¬ä¸å±æ¯åªè¯»ç */68console.log(state1);69console.log(object,'object');70let state2 = readonly(object)71console.log(state2,'origin');72state2.name = 'name';73state2.attr.height = 'height_height'74console.log(state2, 'changed-----');75/*...

shallowReactive.js

Source: shallowReactive.js

...9}10// shallowReactive11// function shallowReactive(obj) {12  // shallowReadonly13function shallowReadonly(obj) {14  return new Proxy(obj, {15    get(obj, key) {16      return obj[key]17    },18    set(obj, key, value) {19      // obj[key] = value;20      // console.log("æ´æ°uiçé¢")21      // return true;22      console.warn(`message:${key}æ¯åªè¯»çï¼ä¸è½èµå¼`)23    }24  })25}26// reactive27// let obj={name:"lnj",age:18};28function reactive(obj) {29  if (typeof obj === 'object') {30    if(obj instanceof Array){31      // å¦ææ¯ä¸ä¸ªæ°ç»ï¼é£ä¹ååºæ°ç»ä¸çæ¯ä¸ä¸ªåç´ ï¼å¤ææ¯ä¸ä¸ªåç´ ææ¯å¦åæ¯ä¸ä¸ªåç°ä¸ªï¼å¦æåæ¯ä¸ä¸ªå¯¹è±¡ï¼é£ä¹ä¹éè¦åè£æProxy32      obj.forEach((item,index)=>{33        if(typeof item=='object'){34          obj[index]=reactive(item)35        }36      })37    }else{38      // å¦æ¯ä¸ä¸ªå¯¹è±¡ï¼é£ä¹ååºå¯¹è±¡å±æ§çåå¼ï¼å¤æå¯¹è±¡å±æ§çåå¼æ¯å¦åæ¯ä¸ä¸ªå¯¹è±¡ï¼é£ä¹ä¹éè¦åè£æproxy39      for(let key in obj){40        let item =obj[key];41        if(typeof item ==='object'){42          obj[key]=reactive(item)43        }44      }45    }46    return new Proxy(obj, {47      get(obj, key) {48        return obj[key]49      },50      set(obj, key, value) {51        obj[key] = value;52        console.log("æ´æ°uiçé¢")53        return true;54      }55    })56  } else {57    console.warn({ message: `${obj}is not object` })58  }59}60let obj = {61  a: 'a',62  gf: {63    b: 'b',64    f: {65      c: 'c',66      s: {67        d: 'd'68      }69    }70  }71};72/**73let state=shallowReactive(obj);74state.a="1"75state.gf.b="2"76state.gf.f.c="3"77 */78// let state = shallowRef(obj)79// state.value.a="1"80// state.value.gf.b="2"81// state.value.gf.f.c="3"82// state.value = {83//   a: 1,84//   gf: {85//     b: 2,86//     f: {87//       c: 3,88//       s: {89//         d: 490//       }91//     }92//   }93// }94// let state=reactive(obj)95// state.a="1"96// state.gf.b="2"97// state.gf.f.c="3"98// let arr=[{id:1,name:'zhangsan'},{id:2,name:'ls'}]99// let state=reactive(arr)100// state[0].name='wangw'101// state[1].name='aaa'102let state=shallowReadonly(obj)...

person.js

Source: person.js

...54export const reactiveReadonly = readonly(objectReactive)55/**56 * person ç shallowReadonly ååºå¼ä»£ç57 */58export const objectShallowReadonly = shallowReadonly(person)59/**60 * reactive ç shallowReadonly ååºå¼ä»£ç61 */62export const reactiveShallowReadonly = shallowReadonly(objectReactive)...

readonly.js

Source: readonly.js

...6        if (obj instanceof Array) {7            //æ°ç»8            obj.forEach((item, index) => {9                if (typeof item === 'object') {10                    obj[index] = shallowReadonly(item)11                }12            })13        } else {14            for (let key in obj) {15                if (typeof obj[key] === 'object') {16                    obj[key] = shallowReadonly(obj[key])17                }18            }19        }20    }21    return shallowReadonly(obj)22}23function shallowReadonly(obj) {24    return new Proxy(obj, {25        get(obj, key) {26            return obj[key]27        },28        set(obj, key, value) {29            console.warn(`objç${key}å±æ§ä¸è½èµå¼`)30        }31    })32}33let data = {34    a: 1,35    b: {36        c: 3,37        d: {38            f: 4,39        }40    }41}42let state = shallowReadonly(data)43state.a = 244state.b.c = 'c'45console.log(state)46let state1 = readonly(data)47state1.a = 248state1.b.c = 'c'49state1.b.d.f = 'f'...

base.js

Source: base.js

...4  return reactive(init)5}6export const store = (init, factory) => {7  const state = createState(deepClone(init))8  return () => shallowReadonly({ state, ...factory(state) })...

useShallow.js

Source: useShallow.js

1import { reactive, shallowReadonly } from 'vue'2export default function useShallow() {3  const n = shallowReadonly(reactive({a:{b:{c:{d:100}}}}))4  // setTimeout(()=>n.a.b.c.d=2000, 2000)5  return n...

Using AI Code Generation

1const { chromium } = require('playwright');2(async () => {3  const browser = await chromium.launch();4  const context = await browser.newContext();5  const page = await context.newPage();6  await page.screenshot({ path: 'example.png' });7  await browser.close();8})();

Using AI Code Generation

1const { chromium, devices } = require('playwright');2(async () => {3  const browser = await chromium.launch();4  const context = await browser.newContext();5  const page = await context.newPage();6  const input = await page.$('input[name="q"]');7  const value = await page.evaluate(input => input.value, input);8  console.log(value);9  await browser.close();10})();11const { chromium, devices } = require('playwright');12(async () => {13  const browser = await chromium.launch();14  const context = await browser.newContext();15  const page = await context.newPage();16  const input = await page.$('input[name="q"]');17  const value = await page.evaluate(input => input.value, shallowReadonly(input));18  console.log(value);19  await browser.close();20})();21const { chromium, devices } = require('playwright');22const { shallowReadonly } = require('playwright/lib/utils/utils');23(async () => {24  const browser = await chromium.launch();25  const context = await browser.newContext();26  const page = await context.newPage();

Using AI Code Generation

1const {chromium} = require('playwright');2(async () => {3  const browser = await chromium.launch();4  const page = await browser.newPage();5  const elementHandle = await page.$('text=Playwright');6  const element = await elementHandle.evaluateHandle((e) => e);7  const innerText = await element.evaluate((e) => e.innerText);8  console.log(innerText);9  await browser.close();10})();11const {chromium} = require('playwright');12(async () => {13  const browser = await chromium.launch();14  const page = await browser.newPage();15  const elementHandle = await page.$('text=Playwright');16  const innerText = await elementHandle.innerText();17  console.log(innerText);18  await browser.close();19})();

Using AI Code Generation

1const { shallowReadonly } = require('playwright/lib/utils/utils');2const obj = { a: 1, b: 2 };3const readonlyObj = shallowReadonly(obj);4readonlyObj.a = 2;5const { shallowReadonly } = require('playwright/lib/utils/utils');6const options = { headless: false };7const readonlyOptions = shallowReadonly(options);8readonlyOptions.headless = true;

Using AI Code Generation

1const playwright = require('playwright');2const { shallowReadonly } = playwright._internal;3const obj = { a: 1, b: 2 };4const readonlyObj = shallowReadonly(obj);5const playwright = require('playwright');6const { deepReadonly } = playwright._internal;7const obj = { a: 1, b: 2, c: { d: 3 } };8const readonlyObj = deepReadonly(obj);9const playwright = require('playwright');10const { isDeepEqual } = playwright._internal;11const obj1 = { a: 1, b: 2, c: { d: 3 } };12const obj2 = { a: 1, b: 2, c: { d: 3 } };13const obj3 = { a: 1, b: 2, c: { d: 4 } };14const playwright = require('playwright');15const { deepClone } = playwright._internal;16const obj = { a: 1, b: 2, c: { d: 3 } };17const clone = deepClone(obj);18const playwright = require('playwright');19const { assert } = playwright._internal;20assert(false, 'This will throw an error');21assert(true, 'This will not throw an error');22const playwright = require('playwright');23const { debugAssert }

Using AI Code Generation

1const { shallowReadonly } = require("@playwright/test/lib/utils/utils");2const { test } = require("@playwright/test");3const { expect } = require("expect");4test("test", async ({ page }) => {5  const obj = { a: 1 };6  const readonly = shallowReadonly(obj);7  expect(readonly).toEqual({ a: 1 });8});9AssertionError: expected { a: 1 } to deeply equal { a: 1 }10const { shallowReadonly } = require("@playwright/test/lib/utils/utils");11const { test } = require("@playwright/test");12const { expect } = require("expect");13test("test", async ({ page }) => {14  const obj = { a: 1 };15  const readonly = shallowReadonly(obj);16  expect(readonly).toEqual({ a: 1 });17});18const { expect } = require("@playwright/test");19const { expect } = require("expect");20const { expect } = require("@playwright/test");21const { expect } = require("expect");22const { shallowReadonly } = require("@playwright/test/lib/utils/utils");23const { test } = require("@playwright/test");24const { expect } = require("@playwright/test");25test("test", async ({ page }) => {26  const obj = { a: 1 };27  const readonly = shallowReadonly(obj);28  expect(readonly).toEqual({ a: 1 });29});

Using AI Code Generation

1const { shallowReadonly } = require('@playwright/test/lib/utils/utils');2const obj = { a: 1, b: 2 };3const ro = shallowReadonly(obj);4const { shallowReadonly } = require('@playwright/test/lib/utils/utils').utils;5test('test', async ({ page }) => {6  const obj = { a: 1, b: 2 };7  page.context().addInitScript(() => {8    window.shallowReadonly = (obj) => {9      for (const key in obj) {10        if (typeof obj[key] === 'object')11          obj[key] = shallowReadonly(obj[key]);12          Object.defineProperty(obj, key, { writable: false });13      }14      return obj;15    };16  });17  await page.evaluate(async () => {18    const obj = { a: 1, b: 2 };19    const ro = shallowReadonly(obj);20  });21});

Using AI Code Generation

1const { shallowReadonly } = require("@playwright/test/lib/utils");2const { chromium } = require("playwright");3const { test } = require("@playwright/test");4test.describe("My Test Suite", () => {5  test("My Test", async ({ page }) => {6    const context = page.context();7    const browser = context.browser();8    const browserContextOptions = browser.options();9    const browserOptions = shallowReadonly(browserContextOptions);10    const browserType = browser.type();11    const browserName = browserType.name();12    const browserPath = browserType.executablePath();13    const browserTypeOptions = browserType.options();14    const browserTypeOptionsShallow = shallowReadonly(browserTypeOptions);15    const browserTypeLaunchOptions = browserType.launchOptions();16    const browserTypeLaunchOptionsShallow = shallowReadonly(browserTypeLaunchOptions);17    const browserTypeDefaultArgs = browserType.defaultArgs();18    const browserTypeDefaultArgsShallow = shallowReadonly(browserTypeDefaultArgs);19    console.log("browserContextOptions", browserContextOptions);20    console.log("browserOptions", browserOptions);21    console.log("browserTypeOptions", browserTypeOptions);22    console.log("browserTypeOptionsShallow", browserTypeOptionsShallow);23    console.log("browserTypeLaunchOptions", browserTypeLaunchOptions);24    console.log("browserTypeLaunchOptionsShallow", browserTypeLaunchOptionsShallow);25    console.log("browserTypeDefaultArgs", browserTypeDefaultArgs);26    console.log("browserTypeDefaultArgsShallow", browserTypeDefaultArgsShallow);27    console.log("browserName", browserName);28    console.log("browserPath", browserPath);29  });30});

StackOverFlow community discussions

Questions

Discussion

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

firefox browser does not start in playwright

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

Running Playwright in Azure Function

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

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

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

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

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

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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.