Interfaces
 InterfaceDescription
 Protectable A Protectable can be run and can throw a error.
 Test A Test can be run and collect its results.
 TestListener A Listener for test progress.
Classes
 ClassDescription
 Assert A set of asserft methods.
 AssertionFailedError Thrown when an assertion failed.
 TestCase A test case defines the fixture to run multiple tests.
 TestFailure A TestFailure collects a failed test together with the caught exception.
 TestResult 
 TestSuite A TestSuite is a Composite of Tests.