Basic JUnit is enahanced with test runners to run tests repeatedly, simultaneously in many threads and with increasing test sizes for asymptotic performance measurements. There are features to measure the time and amount of memory that tests use as well as to record the asymptotic test size parameters. There are some utilities to write these test statistics to various file formats too and these can be found in the listeners package. The main test runner class is TKTestRunner which can be called with command line parameters to specify how tests should be run.