The details page for a single test shows the duration for that specific test.

The details page for a single class shows a table with a list of tests, along with the duration for each test. However, the duration at the top of the class detail page (“Took N seconds”) is not the sum of the durations of tests in that class, but erroneously also includes the durations of tests in all other classes as well (even classes in other packages).

The details page for a package shows a table with a list of classes, with every single class showing the same duration (the duration of the entire job, the same as the class details page). However, the total package duration at the top of the detail page (“Took N seconds”) is the sum of the durations of tests only within that package, and is therefore in general less than the duration shown for a single class within the package.

Finally, the top-level Test Results page shows the proper total duration and the proper duration for each package (matching the package duration shown on the package details page).

This is with a jUnit XML file generated by py.test.