Scripting Cookie Consents

By default synthetic tests behave like a some visiting a site for the first time – the cache is empty, there are no cookies set, localStorage is empty etc.

This empty state means that a Cookie Consent or Consent Management Platform (CMP) dialog is displayed during the test and this introduces two issues:

The dialog often covers up more important content e.g. LCP
Without consent many third-party tags won't load so the influence they have over performance metrics isn't measured.

For these reasons we often recommend adding a script to synthetic tests that sets the appropriate cookies and localStorage entries so that consent manager behave as if a visitor has already given consent for third-parties to load.

A typical script might look something like this:

setCookie	%ORIGIN%	name=value

injectScript	localStorage.setItem("key", "value");

navigate	%URL%

Common Consent Managers

Here's some consent managers we commonly encounter, along with a list of cookies or localStorage entries they use and a snippet of JavaScript that will generate a skeleton SpeedCurve synthetic script.

To use the snippet:

Load the page you want to create a synthetic test for and accept cookies
Open DevTools console, and paste the snippet in (you may have to type allow pasting first)
Execute the snippet. When it completes it will dump the generated synthetic script to the console and also copy the same script to the clipboard
Paste the generated script into the Script field for the URL you're testing

LiveRamp

LiveRamp requires the following localStorage entries to be set

euconsent-v2
cconsent-v2
addtl_consent
gdpr-dau
gdpr-last-interaction
gdpr-config-version
gdpr-auditId
geo-location

Executing this JavaScript snippet in the console, or as a DevTools snippet will generate a skeleton Synthetic Test script and copy it to your clipboard. You can paste the clipboard contents directly into the script field for a URL in site settings.

const items = ["euconsent-v2","cconsent-v2","addtl_consent","gdpr-dau","gdpr-last-interaction","gdpr-config-version","gdpr-auditId","geo-location"]
let commands = items.map(key=>`injectScript\tlocalStorage.setItem('${key}','${localStorage.getItem(key)}');`).join('\n');
commands += "\nnavigate\t%URL%\n"

console.log(commands);
copy(commands);

OneTrust

OneTrust requires two cookies to be set:

OptanonConsent
OptanonAlertBoxClosed

// Cookies
var cookies = document.cookie.split('; ');
var OptanonConsent = cookies.find(entry => entry.startsWith('OptanonConsent='));
var OptanonAlertBoxClosed = cookies.find(entry => entry.startsWith('OptanonAlertBoxClosed='));

// Generate script
var output = 
 `setCookie\t%ORIGIN%\t${OptanonConsent}\n` +
 `setCookie\t%ORIGIN%\t${OptanonAlertBoxClosed}\n` +
 `navigate\t%URL%`;

console.log(output);

copy(output);

Quantcast Choice

Quantcast Choice needs both localStorage entries and cookies to be set

localStorage

CMPList
noniabvendorconsent
_cmpRepromptHash

cookies

euconsent_v2
addtl_consent

// Local storage items
var CMPList = localStorage.getItem('CMPList');
var noniabvendorconsent = localStorage.getItem('noniabvendorconsent');
var _cmpRepromptHash =localStorage.getItem('_cmpRepromptHash');


// Cookies
var cookies = document.cookie.split('; ');
var euconsent_v2 = cookies.find(entry => entry.startsWith('euconsent-v2='));
var addtl_consent = cookies.find(entry => entry.startsWith('addtl_consent='));

// Generate WPT Script
var output = `injectScript\tlocalStorage.setItem('CMPList', '${CMPList}');\n` +
 `injectScript\tlocalStorage.setItem('noniabvendorconsent', '${noniabvendorconsent}');\n` +
 `injectScript\tlocalStorage.setItem('_cmpRepromptHash', '${_cmpRepromptHash}');\n` +
 `setCookie\t%ORIGIN%\t${euconsent_v2}\n` +
 `setCookie\t%ORIGIN%\t${addtl_consent}\n` +
 `navigate\t%URL%\n`;

console.log(output);

copy(output);

TrustArc

TrustArc needs the following cookies to be set:

TAconsentID
notice_preferences
cmapi_cookie_privacy
cmapi_gtm_bl
notice_gdpr_prefs

// Cookies
var cookies = document.cookie.split('; ');
var TAconsentID = cookies.find(entry => entry.startsWith('TAconsentID='));
var notice_preferences = cookies.find(entry => entry.startsWith('notice_preferences='));
var cmapi_cookie_privacy = cookies.find(entry => entry.startsWith('cmapi_cookie_privacy='));
var cmapi_gtm_bl = cookies.find(entry => entry.startsWith('cmapi_gtm_bl='));
var notice_gdpr_prefs = cookies.find(entry => entry.startsWith('notice_gdpr_prefs='));

// Generate WPT Script
var output = 
 `setCookie\t%ORIGIN%\t${TAconsentID}\n` +
 `setCookie\t%ORIGIN%\t${notice_preferences}\n` +
 `setCookie\t%ORIGIN%\t${cmapi_cookie_privacy}\n` +
 `setCookie\t%ORIGIN%\t${cmapi_gtm_bl}\n` +
 `setCookie\t%ORIGIN%\t${notice_gdpr_prefs}\n` +
 `navigate\t%URL%`;

console.log(output);

copy(output);

Usercentrics

Usercentrics requires the localStorage entries to be set:

uc_settings
uc_user_interaction

// Local storage items
var UCSettings = localStorage.getItem('uc_settings');
var UCUserInteraction = localStorage.getItem('uc_user_interaction');

// Generate WPT Script
var output = 
 `injectScript\tlocalStorage.setItem('uc_settings', '${UCSettings}');\n` +
 `injectScript\tlocalStorage.setItem('uc_user_interaction', '${UCUserInteraction}');\n` +
 `navigate\t%URL%\n`;

console.log(output);

copy(output);