Null( object anObject, string message );
Assert.Null( object anObject, string message, object[] parms );

Assert.IsNotNull( object anObject );
Assert.IsNotNull( object anObject, string message );
Assert.IsNotNull( object anObject, string message, object[] parms );

Assert.NotNull( object anObject );
Assert.NotNull( object anObject, string message );
Assert.NotNull( object anObject, string message, object[] parms );

Assert.IsNaN( double aDouble );
Assert.IsNaN( double aDouble, string message );
Assert.IsNaN