Here's an example:
The method does not load any classes from any directories nor does it delete any classes from InterSystems IRIS.
The method executes the tests contained in MyPackage.Tests.
The optional third argument is for qualifiers.
The optional fourth argument is for specifying an individual test method within the test class to execute.
If a test fails, the method continues to execute the remaining test methods, but will break on completion of the tests. So, if you are executing from the Terminal, the Terminal will enter debugging mode.