Mark Michaelis posted a hitlist of things to do to convert from nUnit to VSTS tests in his article Converting a class library to a VSTS Test Project. A big part of this process is understanding the attribute translation:
| nUnit | VSTS |
| [TestFixture] |
[TestClass] |
| [TestFixtureSetUp] |
[ClassInitialize] |
| [TestFixtureTearDown] |
[ClassCleanup] |
| [SetUp] |
[TestInitialize] |
| [TearDown] |
[TestCleanup] |
| [Test] |
[TestMethod] |