!2 Description
Logs on as a specific user.  Part of the initialization for a particular story's setup, and typically referenced in the test suite or story's own setup page.  Unlike Naked Objects' own !-LogonFixture-!, the login specified is ''not'' remembered to the end of the setup.  In order to run tests as a particular login it should therefore appear towards the end of the setup.

!2 Variants
 * SwitchUser
   * is effectively a synonym.

!2 Arguments
 * login name
   * as returned !-DomainObjectContainer#getUser()-!
 * role name(s)
   * can specify up to four.

!2 Columns
 * none

!2 Example Usage
!|logon as|fsmith|

with roles

!|logon as|fsmith|with roles|rpt_mgr_role,admin_role|


