def test_push_locks_previously_unlocked_turnstile():
turnstile = Turnstile(amount_for_passing=10)
turnstile.change_state(Unlocked(turnstile))
turnstile.push()
assert turnstile.current_state() == "locked"
def test_pushing_locked_turnstile_remains_locked():
turnstile = Turnstile()
turnstile.push()
assert turnstile.current_state() == "locked"
def test_turnstile_is_locked_after_creation():
turnstile = Turnstile()
assert turnstile.current_state() == "locked"
def test_insert_coins_keeps_unlocked_turnstile_unlocked():
turnstile = Turnstile(amount_for_passing=10)
turnstile.change_state(Unlocked(turnstile))
turnstile.insert_coin(5)
assert turnstile.current_state() == "unlocked"
def test_insert_more_than_sufficient_coins_opens_turnstile():
turnstile = Turnstile(amount_for_passing=10)
turnstile.insert_coin(15)
assert turnstile.current_state() == "unlocked"
def test_inserting_half_the_required_amount_twice_unlocks_turnstile():
turnstile = Turnstile(amount_for_passing=10)
turnstile.insert_coin(5)
assert turnstile.current_state() == "locked"
turnstile.insert_coin(5)
assert turnstile.current_state() == "unlocked"
def test_insert_insufficient_coins_keeps_turnstile_locked():
turnstile = Turnstile(amount_for_passing=10)
turnstile.insert_coin(5)
assert turnstile.current_state() == "locked"