Use HelloTableView for this.
1) Start with focus on the bottom radio button
- Pressing down arrow should not allow focus to move out of the radio button group
- And continued use of downarrow should not move from button to button

2) Start with focus on the bottom (fourth) radio button
- Press up arrow moves focus to the second button but the third button is selected

3) Start with focus on the top (first) radio button
- Press down arrow moves focus to the third button but the second button is selected
- And pressing down arrow once more moves focus out of the radio button group and the last radio button is selected