Add collision detection, finish line and level up

Task: MIL-005#1
Task: MIL-005#2
Task: MIL-005#3
Task: MIL-005#4

tests/test_player.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-from constants import MOVE_DISTANCE, STARTING_POSITION
+from constants import FINISH_LINE_Y, MOVE_DISTANCE, STARTING_POSITION
 from player import Player
 
 
@@ -27,6 +27,21 @@ def test_go_up_moves_forward_by_move_distance(player: Player) -> None:
     assert player.ycor() == start_y + MOVE_DISTANCE
 
 
+def test_player_is_not_at_finish_line_at_start(player: Player) -> None:
+    assert not player.is_at_finish_line()
+
+
+def test_player_is_at_finish_line_above_finish_y(player: Player) -> None:
+    player.goto(0, FINISH_LINE_Y + 1)
+    assert player.is_at_finish_line()
+
+
+def test_go_to_start_returns_to_starting_position(player: Player) -> None:
+    player.goto(0, FINISH_LINE_Y + 1)
+    player.go_to_start()
+    assert player.position() == STARTING_POSITION
+
+
 def test_go_up_never_moves_sideways(player: Player) -> None:
     for _ in range(5):
         player.go_up()