We highly recommend creating tests for the JavaScript part of your tag, trigger, or variable. Did you want to write tests for the PHP part? Check out our PHP Testing guide.


Because this test suite also runs the regular Matomo JavaScript tracker tests, you need to have an installed Matomo running and ensure the [database_tests] section in yourmatomo/config/config.ini.php is configured correctly, i.e. with the correct password.

The tests will create a database named tracker_tests and store various tracking requests in this DB.

Running tests

To run a test, either open https://matomo.example.com/tests/javascript/ in a browser or execute ./console tests:run-js on the command line.

Creating a test

To create a test, create a new file named plugins/$yourPlugin/tests/javascript/index.php.

You can now define your first test like this:

<script type="text/javascript">
    test("Matomo TagManager DataLayer", function() {
        expect(4); // the number of expected assertions

        var dataLayer = window.MatomoTagManager.dataLayer;

        equal(typeof dataLayer.get, 'function', 'TagManager.get' );
        strictEqual(undefined, dataLayer.get('bazfooooo'), 'DataLayer.get key does not exist' );

        dataLayer.set('foobar3', [5,10,20]);
        deepEqual([5, 10, 20], dataLayer.get('foobar3'), 'DataLayer.get can return object' );
        ok(!!dataLayer.values, 'DataLayer has values');

    test("AnotherCategory", function() {

The main methods you will need to create tests are:

You can find more information in the QUnit API Documentation

Testing a tag

You may test a tag using the method TagManagerTestHelper.fireTemplateTag(tagName, parameters) like this:

var customHtmlParameter = TagManagerTestHelper.buildVariable('<div id="customHtmlTag1">my foo bar baz test</div>';

// configure the required parameters for this tag, if any
var params = {customHtml: customHtmlParameter)};

 // replace `CustomHtmlTag` with the name of your tag
TagManagerTestHelper.fireTemplateTag('CustomHtmlTag', params);

// we now verify the element was added by this tag
var addedElement1 = document.getElementById('customHtmlTag1');

strictEqual('my foo bar baz test', addedElement1.innerText, 'should have added the element');

Testing a trigger

You may test a trigger using the method TagManagerTestHelper.setUpTemplateTrigger(triggerName, parameters, callbackWhenEventTriggered) like this:

// your trigger may or may not require a parameter
var parameters = {};

// the callback will be executed when ever the trigger triggers an event
var events = [];
var callback = function (event) { events.push(event); };

// replace `JavaScriptErrorTrigger` with the name of your trigger
TagManagerTestHelper.setUpTemplateTrigger('JavaScriptErrorTrigger', parameters, callback);

// now we fake an error
window.onerror('Uncaught Error: The error', 'https://matomo.org/tag/manager.js?cb=348181', 53, 19, new Error('The error'));

// now we ensure the error was added
    "event": "mtm.JavaScriptError",
    "mtm.errorLine": 53,
    "mtm.errorMessage": "Uncaught Error: The error",
    "mtm.errorUrl": "https://matomo.org/tag/manager.js?cb=348181"
}], events, 'should have triggered an event');

Testing a variable

You may test a variable using the method TagManagerTestHelper.resolveTemplateVariable(variableName, parameters) like this:

// configure the required parameters for this tag, if any
var params = {constantValue: TagManagerTestHelper.buildVariable('mytest')};

// replace `ConstantVariable` with the name of your variable
var variable = TagManagerTestHelper.resolveTemplateVariable('ConstantVariable', params);

// assert the correct value was returned by the variable
strictEqual('mytest', variable, 'returns any passed value');

Mocking document or window

As recommended in the guides on how to create a tag, trigger, or variable, you should not access document or window within your template directly but instead parameters.document and parameters.window. This allows you to set a custom document or window in the tests.

Document example

Inject a custom document may be helpful when for example testing a variable which retrieves values from a cookie or referrer:

// we fake the set document
var params = {document: {cookie: 'mytest=foobar; loginbaz=helloworld'}};
params.cookieName = TagManagerTestHelper.buildVariable('mytest');

strictEqual('foobar', TagManagerTestHelper.resolveTemplateVariable('CookieVariable', params));
var referrerUrl = 'https://apache.matomo:80/index.php?module=CoreHome&action=index&idSite=1&period=day';
var params = {document: {referrer: referrerUrl}};
strictEqual(referrerUrl, TagManagerTestHelper.resolveTemplateVariable('ReferrerUrlVariable', params));

Window example

Instead of polluting the global name space, we set the variable as part of the parameters:

var params = {window: {myvar1: 'myfootest'}};
params.variableName = TagManagerTestHelper.buildVariable('myvar1');

strictEqual('myfootest', TagManagerTestHelper.resolveTemplateVariable('JavaScriptVariable', params));

It may also be useful to fake a custom location:

var theLocation = {"href":"https://apache.matomo:81/index.php?module=CoreHome&action=index&idSite=1&period=day#foobarhash","ancestorOrigins":{},"origin":"https://apache.matomo","protocol":"https:","host":"apache.matomo","hostname":"apache.matomo","port":"81","pathname":"/index.php","search":"?module=CoreHome&action=index&idSite=1&period=day","hash":"#foobarhash"};

// here we mock a location
var params = {window: {location: theLocation}, urlPart: TagManagerTestHelper.buildVariable('href')};

strictEqual(theLocation.href, TagManagerTestHelper.resolveTemplateVariable('UrlVariable', params));

Triggering an event

Sometimes you may need to trigger an event manually. For example, you want to test a mouse movement but cannot actually move the mouse. In this case you may trigger an event programmatically like this:

var target = document.getElementById('myelement');
var customParams = {clientY: 2, clientX: 5}; // set to null if no custom params
var bubbles = true;
TagManagerTestHelper.triggerEvent(target, 'mouseleave', customParams, bubbles);

Asynchronous or delayed events

In some cases you may have to wait for a specific event to occur as it is executed with a delay. For example a scroll might be triggered only after 100ms. To do this, you can temporarily "stop" and "start" the test execution:

window.scrollTo(0, 200);

var waitForMs = 400;
setTimeout(function () {
    strictEqual(1, scrolls1.length, 'onScroll, all registered event handlers receive events');
}, waitForMs);