No, it is not for all variables. I hovered over an int[] and I was able to see the values inside, but not for a List<string>. Just to test this issue, I assigned an int named "A" the value of 4. I could not see the value of A by hovering over it.
The way I got to this point is by right clicking on the left margin > Advanced > Debug covering test in existing task runner...
If I use the standard MSTest debugging, I'm able to see all the values of these variables.
This is on Windows 10 Pro, Version 1709, Build 16299.371.
It's possible that this is caused by a metadata issue with the PDBs. Previously, where we've seen these problems it's been related to compiler generated structures such as async/await and yield. If you're able to isolate this problem in code that you can share with me, I can take a closer look to try and understand it better.
Unfortunately, the debugger is a bit of a black box to us. Even when the PDB structure is correct, sometimes weird things can happen in certain environments. Reproducing these problems with consistency can often prove difficult to do.