If you want to learn how to write test codeunits, then the best place to start is in Luc van Vugt's blog Van Vugt's dynamiXs.
You also find a few presentations about the subject on youtube,If you prefer video.
Not much experience my self with testing approval workflows with the test toolkit. But maybe Luc van Vugt has tried it?
NAVSkills Webinar: In this webinar Luc van Vugt is explaining the table object in Dynamics NAV. This is part 2 of the 101 series for C/Side development.
And which day other than the release of Dynamics 365 Business Central, would…
The next episodes:
The foundation of any system is the data structure definition. In NAV, the building blocks of this foundation are the Tables. A NAV table includes much…
One of the most frequently asked questions is how to get started programming Microsoft Dynamics NAV. MVP Luc van Vugt has made a video about just that. First part together with long time DUG member David Studebaker.