I have a new best friend. Now instead of writing
Assert.AreEqual(filesExpected.Count, filesReturned.Length);
Assert.In(filesExpected[0], filesReturned);
Assert.In(filesExpected[1], filesReturned);
Assert.In(filesExpected[2], filesReturned);
Assert.In(filesExpected[3], filesReturned);
Assert.In(filesExpected[4], filesReturned);
With mbUnit I can simply write
CollectionAssert.AreEquivalent(filesExpected, filesReturned);
In fact a quick look to see what other documentation there is produces Phil Haack's more thorough examination, that still feels like its only just scratching the surface.