test('be 1 if all frets are within adjacent strings', () => {
    const horizontalFrets = new HorizontalFrets([
      new Fret(GuitarString.Fourth, 2, Pitch.E),
      new Fret(GuitarString.Fifth, 3, Pitch.C),
      new Fret(GuitarString.Third, 2, Pitch.BFlat),