After upgrading to R#9 i have seen very inconsistent behavior for executing tests. It's like running the tests just "doesn't work". It seems like if the test window needs to build anything, it really goes haywire and just spins and spins and spins. If i build myself, then run the tests it usually works. However there's also times I need to close all the test sessions and run the tests from the visual studio bubbles again to get them to work.
When i disabled shadow copy these issues went away.