Synthetic update: Support for %TEST_ID% scripting variable, and windowed CLS

25th May 2023 (UTC)

%TEST_ID% added as scripting variable

Some customers wanted to be able to match their synthetic tests to their server-side logs and monitoring applications, so to help them we've added the %TEST_ID% variable to synthetic scripting.

%TEST_ID% contains the id of the current test e.g. 230524_1F_1bff7967655cdf8ec75704406a3f2819, and can be added as query parameters, headers, cookies etc.

Adding the test id as a query parameter:

navigate    %URL%?tag=%TEST_ID%

Adding the test id to a cookie

setCookie   %ORIGIN% tag=%TEST_ID%
navigate    %URL%

Variables can help make synthetic scripts re-usable and reliable and you can find out more about them in our scripting reference

Windowed CLS

The measurement of Cumulative Layout Shift (CLS) now uses the windowed measuring approach that RUM already uses Evolving the CLS metric

Some tests may see CLS values improve slightly as a result of this change, but most values won't change.