public void NextIndex_Test()
{
Assert.Equal(1, Notes.C.NextIndex);
Assert.Equal(2, Notes.D.NextIndex);
Assert.Equal(3, Notes.E.NextIndex);
Assert.Equal(4, Notes.F.NextIndex);
Assert.Equal(5, Notes.G.NextIndex);
Assert.Equal(6, Notes.A.NextIndex);
Assert.Equal(0, Notes.B.NextIndex);
}