Until recently, I have been having issues debugging unit tests with ReSharper. Luckily, I stumbled across the answer which is in ReSharper configuration. By default, ReSharper is set to use the current startup project when debugging unit tests. Since I am working with a web project and trying to debug unit tests in an assembly that is not the web site project, it would start the web site when I started to debug a unit test, opening the browser to the site which is not at all what I wanted. To fix it turned out to be as easy as changing the configuration to "Use the project being tested" in the ReSharper Unit Testing options as highlightd on the screen capture.