Create a naming pattern for the objects your tests generate. This makes it easier to track and deconflict more than one user or test suite at a time in your identity system. For example, name the test user using the row or item number in a test plan, such as tuser-1 and so on. This allows you to identify the user in a trace if there are issues.
It is also recommended that you use a Variable for your object names which might be defined at the top of each test. This allows you to change the test object name easily if necessary. This method also allows you to use a template test to create and delete test users. See Using Templates.