For a long time, xUnit’s dev has resisted adding support for skipping a test dynamically. You could create your own Fact class and handle that yourself, but that was quite a lot of work, for something very specific.
In RavenDB, we had the need to dynamically decide whatever the test can run based on the actual test situation, so I decided to add this to our xUnit fork. This turned out to be really simple to do. Just three lines of code