I do my unit and suite testing in Design mode. Is this a good practice?

When working as a designer in VLF-WIN additional menu options appear, security is disabled and additional features that use more resources are enabled.

When doing unit or suite testing you should always use the UF_EXEC (user) entry point form so that you experience the same environment that a real end-user would.

Equally, when working in VLF-ONE do not use developer=yes on your testing URLs.