Flexible publish plugin: how to check boolean condition?

I have defined a Boolean Parameter ‘runTests’ for a Jenkins job. Now, if this parameter is selected (true), I want to run my tests and publish test results. I am using the Flexible publish plugin for this, and have defined a Conditional action using a Boolean condition. However, I do not exactly know how I should write the test for the condition in the Token field. I currently have written:


but this fails with

Exception caught evaluating condition: [org.jenkinsci.plugins.tokenmacro.MacroEvaluationException: Error processing tokens], action = [Fail the build]

How exactly should I check the value of the runTests environment variable for true or false in the Token field?