def test_next_previous_buttons(base_url, selenium):
page = TVPage(base_url, selenium).open()
assert not page.is_previous_enabled
screens = page.screens
thumbnails = page.thumbnails
for i in range(len(screens) - 1):
assert screens[i].is_displayed
assert thumbnails[i].is_selected
page.show_next_screen()
assert not page.is_next_enabled
for i in range(len(screens) - 1, 0, -1):
assert screens[i].is_displayed
assert thumbnails[i].is_selected
page.show_previous_screen()
assert not page.is_previous_enabled
assert screens[0].is_displayed
assert thumbnails[0].is_selected
