I am nut sure if this is a bug, or if there is a way around, but it is a challenge anyway.
I have a mutation that takes no payload. (It just clears a list.)
It looks like this doesn't work properly in an actionGroup.
I think the problem is that there is no payload to add the actionGroup in, and at the moment I am not able to add an empty object as payload.
As a workaround I add a dummy payload, but it would be nice to have a better way.
Also, in the documentation it is referred to test/test-action-group-undo.js. This file does not exist.