I was researching on a popular agile method, Kanban but I couldn't really find any helpful material. Most importantly, I don't really get how WIP can be helpful in Kanban.

According to [this wikipedia article](https://en.wikipedia.org/wiki/Kanban_(development)), *Kanban advocates limiting work in progress, which as well as reducing waste due to multitasking and context switching, exposes operational problems and stimulates collaboration to continuously improve the system.*

This explanation about WIP came off as strange to me, because, I think, it's assuming that one worker is supposed to be working only on one of the whole Kanban stages, such as "to do", "development", "test", "finished" rather than take one item and take care of it over the whole stages. I think only two stages among them, which are "development" and "test", are the stages where you do work. So if you are working on "test" stage, is that the job you are supposed to do all day long without touching "development" process at all? It seems too rigid.. Is that really how agile companies out there work?