My project specifies TestNG 6.10, and yet Gradle 4.10.2 is running with TestNG 6.9.9
This seems to be a bug in Gradle. I haven’t found any way to specify TestNG version beyond the expected dependency mechanism.
Running the same code from Maven, I get TestNG 6.10 - as expected.
It appears that the problematic instance of TestNG is bundled into the ‘selenium-server-standalone’ uber-JAR. This doesn’t cause problems in Maven, but in Gradle this uber-JAR is apparently getting placed on the class path ahead of the explicit TestNG dependency. Consequently, I end up running my tests in TestNG 6.9.9.