As what I searched for is not supported at the moment, I made the next workaround:
- build the project
- run MSText for all tests -> .trx output
- simple winforms/wpf program, which parses .trx, gets the test cases and displays them in a treeview
- now we can run mstest from this application for the selected node -> creates .trx output (which can be opened in VS)
I used .trx because that way I don't have to do parse the assembly, mstest.exe does it. Test categories are made this way:
[TestCategory("MainTestType")]
[TestCategory("MainTestType/SubTestType")]
[TestCategory("MainTestType/SubTestType/SubsubTestType")]
So the is the workaround which is simple, only one binary and the developers can use too. The problem with playlist was that they aren't hierarchical neither.