getListeners

Fully qualified classes that are TestNG listeners (instances of org.testng.ITestListener or org.testng.IReporter). By default, the listeners set is empty. Configuring extra listener:

plugins {
    id 'java'
}

test {
    useTestNG() {
        // creates emailable HTML file
        // this reporter typically ships with TestNG library
        listeners.add('org.testng.reporters.EmailableReporter')
    }
}