Assert.IsInstanceOf

Assert.IsInstanceOf succeeds if the object provided as an actual value is an instance of the expected type.

Assert.IsInstanceOf( Type expected, object actual );
Assert.IsInstanceOf( Type expected, object actual, 
                         string message, params object[] parms );
Assert.IsInstanceOf<T>( object actual );
Assert.IsInstanceOf<T>( object actual, 
                        string message, params object[] parms );			

See also...

* Type Constraints