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marko-tester Build Status

Test library to assist with testing marko-widget UI components and more.


Start using marko-tester with:

npm install --save-dev marko-tester


Once you've installed marko-tester, you can start using the markotester alias with the path to your source folder. There are few arguments you can pass if needed:

  • --no-coverage if you don't want to generate coverage report
  • --no-mocha if you want to execute only linting
  • --no-lint if you don't want lint checks
  • --lint-es6 if you want to lint your es6 code
  • --fix-lint if you want to automatically fix your linting issues
  • --fix-fixtures if you want to automatically replace failing fixtures with actual render result
  • --with-acceptance for running acceptance tests (keep in mind, with this flag in place unit-tests won't be executed)
markotester source --no-coverage
markotester source --no-coverage --no-lint
markotester source --with-acceptance
markotester source --fix-lint
markotester source --fix-fixtures

File structure

|- source
|  |- components
|  |  |- phone-frame
|  |  |  +- test
|  |  |     |- fixtures
|  |  |     |  |- default.json
|  |  |     |  |- default.html
|  |  |     |  |- empty.js
|  |  |     |  +- empty.html
|  |  |     +- index.spec.js
|  |  |- browser.json
|  |  |- index.js
|  |  +- template.marko
|  +- pages
|     +- mobile-preview
|        |- test
|        |  |- acceptance.js
|        |  |- renderer.spec.js
|        |  +- widget.spec.js
|        |- browser.json
|        |- renderer.js
|        |- template.marko
|        +- widget.js
+- .marko-tester.js

Configuration file

You can find an example configuration file in the root folder of marko-tester:

'use strict';

module.exports = {
  taglibExcludeDirs: [
  taglibExcludePackages: [
  excludedAttributes: ['data-widget'],
  lassoPlugins: [],
  onInit: function onInit() {},
  onDestroy: function onDestroy() {},
  coverage: {
    reporters: [
    dest: '.coverage',
    excludes: [
  acceptance: {
    baseUrl: 'localhost:8080',
    startCommand: 'npm start',
    stopCommand: 'npm stop',
    startTimeout: 10000
  • components - An array of patterns where to search for components that should be loaded into jsdom page.
  • taglibExcludeDirs - An array of paths relative to the root of your project folders that contain marko.json. This is used to isolate your tests so the nested components won't be renderer.
  • taglibExcludePackages - An array of module names. This is used to isolate your tests so the nested components won't be renderer.
  • excludedAttributes - An array of HTML attributes that can be different every test execution (e.g data-widget which marko dynamically changes based on package version). (Default: ['data-widget'])
  • lassoPlugins - An array of lasso plugins to require and attach to lasso configuration during client test execution.
  • onInit - A hook that will be executed before every it when the widget needs to be instantiated.
  • onDestroy - A hook that will be executed after every it when the widget needs to be destroyed.
  • coverage.reporters - An array of reporters for istanbul to use. (Default: ['text-summary', 'html', 'json-summary'])
  • coverage.dest - The target destination folder where reports will be written. (Default: .coverage)
  • coverage.excludes - An array of file patterns to exclude from istanbul reports. (Default: ['**/*.marko.js'])
  • acceptance.baseUrl - An URL to load when browser starts. (Default: localhost:8080)
  • acceptance.startCommand - A command to execute before starting selenium server. (Default: npm start)
  • acceptance.stopCommand - A command to execute after stopping selenium server. (Default: npm stop)
  • acceptance.startTimeout - An amount of milliseconds to wait before starting selenium server. (Default: 10000)

Automatic component/fixtures search

Marko-tester will try to automatically find your component renderer and/or fixtures to test. For the renderer, marko-tester will go up one level from your spec file and search for either index.js or renderer.js.

Fixtures will be automatically found if they are inside the fixtures folder on the same level as your spec file.

Render comparison based on specific input

The rendering test works by giving your template the input to use for rendering and then comparing output with the specified HTML.

The JSON file and HTML file comprising a test should follow the pattern below (check the fixtures folder in File Structure section):


Your test file will have to invoke the testFixtures function. Below you can find an example of how your spec might look:

'use strict';

global.tester('source/components/phone-frame', function() {

Component client-side testing

The client test works by instantiating a marko-widget and testing the functionality against it. For that browser environment is needed, for those purposes marko-tester uses jsdom to render the lasso-generated page and expose window object.

During client testing, marko-tester gives you a few methods to utilize:

  • buildPage - Will create an empty page, giving you access to window and document objects. This method is available right after test case declaration.
  • buildComponent - Used to build the page with the component constructor in it. At this point, the Widget attribute will be exposed to the mocha context giving you access to your Widget's prototype. This method is available right after test case declaration.
  • buildWidget - Will instantiate the widget on the page and expose the widget attibute to the mocha context with the instance of your widget. This method is available within buildComponent context.
'use strict';

global.tester('source/components/phone-frame', function(expect, sinon) { // you can request `sinon` or `expect` just by adding the respective param;

  // this.buildPage - is available here;
  // this.fixtures - will give you a list of attached test fixtures to this component;

  this.buildComponent(function() {
    var mockHello = 'world';

    beforeEach(function() {
      this.Widget.prototype.hello = mockHello;

    afterEach(function() {
      delete this.Widget.prototype.hello;

    this.buildWidget(function() {
      it('should have hello attribute', function() {

By default, running this.buildComponent will build the component using the default fixture (if there is one). If you wish to build the component using a different fixture, you can pass an option to do that before the callback:

  fixture: {}
  // It can be either a fixture object or a string with a relative path to the fixture.
  // Do not forget that you can also utilize the "this.fixtures" data.
}, function () {});

Few additional features

  1. tester, buildComponent, buildPage and buildWidget commands will create a mocha's describe function. That's why the only and skip operators can be used with these commands the same way as with describe (e.g this.buildComponent.only(...), tester.skip(...)).

  2. tester command on callback along with sinon and/or expect can expose rewire and mockRequire functions for you in order to rewire or mock necessary module you using in your implementation. Note: that only will work during server-side testing.

  3. Another thing you can utilize from tester callback is modRequire. You can require files that were compiled by lasso, so it is only available when page was constructed (after execution of buildComponent and/or buildPage):

global.tester('util', function (modRequire) {
  this.buildPage(function () {
    var util;

    beforeEach(function () {
      util = modRequire('src/util');

  1. If you want to mock require during client-side testing - you can do that using options for buildComponent method. There as a key you can pass relative path to the necessary file that will be required. And the mock of that file as a value. Keep in mind that mocked require will only exist within this buildComponent.
  mockRequire: {
    '../dep': { hello: 'world'}
}, function() { ... });
  1. You can also use a different file layout if necessary. When your template has a top-level element of tbody, tr, or something else that expects a table element as a parent, you can add the layout parameter and set it to table. This will ensure JSDOM renders your component correctly.
  fixture: this.fixtures.basic,
  layout: 'table'
}, function() { ... });

Code style (linting)

Apart from testing, consistent styling is another important part of keeping high quality code. For that particular reason, marko-tester comes with an eslint and stylelint checks built-in. It will check the style of your code when you execute the markotester command.

It uses legacy (es5) airbnb configuration for ESLint and standard configuration for Stylelint (checkine both less and css files).

Acceptance tests

Thanks to webdriverio and selenium-standalone, we have the ability to easily write acceptance tests in the same manner that we do our unit tests.

To do that, we have a small configuration within our .marko-tester.json file under the acceptance key. Configure it for your project, if needed. Create a file called acceptance.js with test cases in your test folder. The syntax remains the same as with unit-tests. The only difference is that you will have the browser argument available to you in the tester method callback. Tha argument will give you a configured webdriver, as soon as you execute it.

'use strict';

global.tester('source/pages/index', function(expect, browser) {
  var page;

  before(function () {
    page = browser().url('/hello-world');

  it('should have a title', function (done) {
    expect(page.getTitle())'hello world').and.notify(done);