not seeing any TestNG output after running "./gradlew test"?

Causes: 

Gradle build script is not properly configured to run TestNG. 

Debugs:

Debug-1:

Check if the TestNG dependency is correctly added to the build.gradle file, and if the test task is properly defined with the TestNG test runner. 

Debug-2:

make sure that the test output directory is properly configured in the build.gradle file.

Debug-3:

Another possible reason could be that there are no TestNG tests in the project or the tests are not properly annotated with the @Test annotation.