Events specific for JUnit unit testing framework are displayed on the "JUnit" tab. The tab is not visible if there are no JUnit events in the build.
"JUnit summary" shows total JUnit duration, the total number of tests and the number of failed tests. Longest tests are presented as bar chart. They are clickable, and you can navigate to the build timeline, and see their position among other events.
Tests by class
The "Test by class" section groups tests by full qualified class name and shows traces of build events where they were originated.
For every test class the "Duration" column displays sum of durations of all test methods in the class.
"Tests" section shows plain list of all tests sorted by their duration.