Click on the panel left to the line number where you want to add that breaker icon.
not that there is no test tube icon on the left panel how do i run a test in debug mode?
You need to wait for sometime. Try restarting the IDE. And then wait for sometime and let it do its work.
Or you can go to PortfolioManagerApplicationTest.java and there will 2 options over each class namely Run test and Debug test. You can also run it from there