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    3.0.1 • Public • Published



    What is this repository for?

    How do I get set up?

    1. Go to existing node project where you want to install test-juggler. In case of having tests in seperate project, go to empty folder and run "npm init --yes", to create new project.
    2. Run "npm install test-juggler"
    3. Run "npx jest" to run example tests.
    4. For installing framework without copying examples (i.e. for continious integration), set environment varaible "DO_NOT_INSTALL_EXAMPLES = true" before installing.

    Default Timeout

    • Default time in milliseconds for Playwright to wait for an element can be set in test-juggler.config i.e. defaultTimeout: 10000

    Performance Tracing

    • To enable Chrome performance tracing set useTracing to true in test-juggler.config
    • Chromium does not support tracing of different tabs in parallel, so this option will only work when tests are run in serial mode
    • Use "jest --runInBand" as your "test" command to run tests serially

    Screenshot Capturing

    • Set captureScreenshots: true in test-juggler.config to enable capturing screenshots on every action.
    • Note that screen capture does not work well with headful browser mode.
    • There might be some performance degradation when using screenshots capturing.

    Visual regression functionality

    Retrying actions

    • Helpers.retry() allows to retry any async function.
    • By default it uses exponential factoring, i.e. every next timeout is twice as long.
    • Use retry as last resort, when tests depends on flaky third party behaviour.

    Waiting for full page load

    • Helpers.goToUrlAndLoad() waits for page to be fully loaded.
    • It uses parameter 'waitUntil: "networkidle"' to consider navigation to be finished when there are no more than 0 network connections for at least 500 ms.

    Intercept requests

    • Interceptor helper introduced to take some actions with requests and responses:
    • interceptor.abortRequests() allows to abort all requests or requests by url glob pattern, regex pattern (More inforamtion in Playwright documentation)
    • interceptor.abortRequestsDuringAction() allows to abort all requests or requests by url glob pattern, regex pattern when specific action is being performed (More inforamtion about url matching in Playwright documentation)
    • interceptor.getAllRequestsData() allows to get all requests information when specific action is being performed.
    • interceptor.waitForRequestAfterAction() waits for specific or any first request and returns all its data.
    • interceptor.waitForResponseAfterAction() waits for specific or any first response and returns all its data.

    API testing

    • apiHelpers class uses Axios library for issuing HTTP requests.
    • apiHelpers.request() can be used for sending arbitrary HTTP requests.
    • apiHelpers.get(), apiHelpers.post(), apiHelpers.put() and apiHelpers.delete() are shortcuts for most common request types.
    • Refer to https://github.com/axios/axios documentation for more complex scenarios.

    Enable console logs

    • Console logs are available by default.
    • Console message types: console, pageerror, response when statuses are > 399, requestfailed.
    • Console logs are not displayed if new page is initiated in test:
    page = await browser.newPage();

    In that case console logs can be enabled using method:


    Parallel execution

    • By default Jest runs tests in parallel with a worker pool of child processes
    • The console commands responsible for parallelization settings (Official Jest documentation):

    -maxConcurrency= (Default: 5) Prevents Jest from executing more than the specified amount of tests at the same time. Only affects tests that use test.concurrent.

    -maxWorkers=| Specifies the maximum number of workers the worker-pool will spawn for running tests. In single run mode, this defaults to the number of the cores available on your machine minus one for the main thread. In watch mode, this defaults to half of the available cores on your machine to ensure Jest is unobtrusive and does not grind your machine to a halt. It may be useful to adjust this in resource limited environments like CIs but the defaults should be adequate for most use-cases. For environments with variable CPUs available, you can use percentage based configuration: --maxWorkers=50%

    • Create at least 21 test files and invoke with --maxWorkers=4 to run tests on 4 threads for example. That should be enough to trick Jest into running your tests always in parallel. (Source)
    • Running with --no-cache it always seems to run in parallel (as long as there are at least two files anyway). (Source)

    Junit report

    • junit report is generated on every test run. Report can be found in junit-report/junit.xml. Path and other parameters can be changed. More info:(Source)

    Running tests sequentially

    Run tests in different projects

    There is possibility to add several Jest projects (Official Jest documentation). In case there is need to have E2E tests and Unit tests in one solution, or one project to run tests sequentially and another project to run tests in parallel. This can be helpful for setuping CI/CD.

    Example of parallel and sequential projects run: jest.config.js example:

    module.exports = {
        projects: [
                displayName: "default-tests",
                globalSetup: "./test-environment/setup.js",
                globalTeardown: "./test-environment/teardown.js",
                testEnvironment: "./test-environment/environment.js",
                setupFilesAfterEnv: ["./test-environment/jest.setup.js"],
                transformIgnorePatterns: ["node_modules/(?!(test-juggler)/)"],
                verbose: true,
                testTimeout: 60000
                displayName: "serial-tests",
                testMatch: ["**/?(*.)+(serial-test).[jt]s?(x)"],
                globalSetup: "./test-environment/setup.js",
                globalTeardown: "./test-environment/teardown.js",
                testEnvironment: "./test-environment/environment.js",
                setupFilesAfterEnv: ["./test-environment/jest.setup.js"],
                transformIgnorePatterns: ["node_modules/(?!(test-juggler)/)"],
                verbose: true,
                testTimeout: 60000
        reporters: ["default", ["jest-junit", { outputDirectory: "junit-report" }]]

    Add several scripts in package.json file under "scripts":

    "default-tests": "jest --selectProjects default-tests",
    "serial-tests": "jest --selectProjects serial-tests --runInBand",
    "all-tests": "npm run default-tests && npm run serial-tests",


    • Type and run npm run default-tests to run all default tests
    • Type and run npm run serial-tests to run all serial tests
    • Type and run npm run all-tests to run all projects in one batch (serial tests will run sequentially)
    • Type and run npm run test to run all projects in one batch (all tests in parallel)

    Note 1: Parallel and sequantial run can be implemented without projects. Add test files matchers in jest scripts. Example:

     "serial-tests": "jest --testRegex '.*serial-test*' --runInBand",
     "all-tests": "npm run test && npm run serial-tests",


    "all-tests": "jest && jest --testRegex '.*serial-test*' --runInBand",

    Note 2: When running two scripts at once then latest test run overrides junit report. So user is unable to find information about first run. To resolve this problem and generate unique report after each test run add setting uniqueOutputName to jest-junit configuration in jest.config.js file:

    reporters: ["default", ["jest-junit", { outputDirectory: "junit-report", uniqueOutputName: "true" }]]

    Contribution guidelines

    • Contribution should be done and tested in feature branch
    • PR review is required to merge to Master
    • All code should be covered in Unit tests

    Who do I talk to?


    npm i test-juggler

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