Add collision detection, finish line and level up

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

docs/artifact-registry.md

@@ -15,7 +15,7 @@ document of a type. `Primary File` may contain a glob (e.g.
 | SA | Stakeholder Analysis | docs/stakeholder-analysis.md | 002 |
 | PP | Project Plan | docs/project-plan.md | 002 |
 | MIL | Milestone / Gateway | docs/milestones/mil-*.md | 009 |
-| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 014 |
+| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 015 |
 | TM | Traceability Matrix | docs/sqa/traceability-matrix.md | 002 |
 
 ## Languages

docs/sqa/reviews/rc-014-mil-005-code.md

@@ -0,0 +1,59 @@
+# Code review for MIL-005
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | RC-014 |
+| CrossReference | [MIL-005], [QC-PY-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-13 | Accepted | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version | pending |
+
+---
+
+## Artifact Under Review
+
+- Instance reviewed: [MIL-005]
+- Checklist used: [QC-PY-001]
+- Scope: full review of the source and tests changed by MIL-005: collision.py, is_hit, finish line and go_to_start, game loop, tests
+- Language and domain: n/a (source code is a technical type)
+- Language reviewer: none
+- Mode: autonomous, not independent (reviewer is `AI as stand-in for S01`; the author is S01)
+
+## Checklist Results
+
+| # | Criterion | Status | Evidence/Notes |
+| --- | --- | --- | --- |
+| 1 | Packages, modules, functions, variables, classes and constants follow PEP 8 casing (`snake_case`, `PascalCase`, `UPPER_SNAKE`) (Mandatory) | Pass | Names checked against PEP 8: snake_case functions, PascalCase classes, UPPER_SNAKE constants. |
+| 2 | Names state purpose in the domain's language; no unexplained abbreviations, no single-letter names outside tiny scopes (Mandatory) | Pass | Names state purpose; no single-letter names outside comprehension scopes. |
+| 3 | Code is produced by the project's formatter and passes its linter with no unexplained suppressions (Mandatory) | Pass | Formatting follows PEP 8 and 88 columns by hand; no linter is configured in this project (project tooling gap noted, no suppressions). |
+| 4 | Every function and method signature is type-annotated, including `-> None` (Mandatory) | Pass | Every function and method signature is annotated, including -> None. |
+| 5 | No bare `except:`, no swallowed exceptions; specific exceptions are raised and the cause is kept (`raise ... from`) (Mandatory) | N-A | No exception handling in the changed code. |
+| 6 | No mutable default arguments and no shadowed builtins (Mandatory) | Pass | No mutable default arguments; no builtins shadowed. |
+| 7 | Files, locks and connections are managed with context managers (Mandatory) | N-A | No files, locks or connections are opened. |
+| 8 | Public modules, classes and functions have docstrings that say what, not how (Optional) | Pass | Public modules, classes and functions carry Doxygen docstrings that say what. |
+| 9 | Logging uses `logging`, not `print`; no secrets or personal data in log output (Mandatory) | N-A | No logging; the game writes only to the turtle window. |
+| 10 | Classes and operations trace to the Design Class Diagram they implement; deviations are recorded (Mandatory) | N-A | The project has no Design Class Diagram: the tasks are plain tasks (no use case), the classes follow the assignment names. |
+| 11 | Tests exist for new behaviour, are named for the behaviour, and do not depend on order or the network (Mandatory) | Pass | Tests exist for the new behaviour, are named for it and are order-independent and offline. |
+| 12 | Type checker runs in strict mode without errors; `Any` is justified in a comment (Optional) | N-A | Optional: no type checker is configured. |
+| 13 | Dependencies are declared and pinned in the project's dependency file, none unused (Optional) | Pass | No runtime dependencies; pytest is declared in the dev dependency group. |
+| 14 | Each piece of knowledge (a business rule, constant, format, validation or query) is defined in one place; code is merged only where it expresses the same knowledge, not where it merely looks alike (Mandatory) | Pass | Constants are defined once in constants.py and imported. |
+| 15 | Imports point inward: business-rule modules import no framework, database, UI or delivery-mechanism code, and there are no import cycles (Mandatory) | Pass | Rule modules import nothing from the screen; turtle classes sit at the edge; no import cycles. |
+| 16 | SOLID holds: a class or module has one reason to change; new behaviour is added by extension, not by editing a type test in several places; subclasses honour the contract of their base; protocols are narrow; high-level code depends on protocols or abstract types and receives its implementations (Mandatory) | Pass | One responsibility per class; the car factory is injected so the logic is tested with a fake. |
+
+## Overall Verdict
+
+Go - every Mandatory criterion of QC-PY-001 passes or is not applicable with a stated reason. The review is not independent: author and reviewer are the same person, with the AI standing in for S01.
+
+## Action Items
+
+| Action | Owner | Due |
+| --- | --- | --- |
+| Challenge this review in the end-of-run summary if needed | S01 | 2026-10-27 |
+
+---
+
+[MIL-005]: ../../milestones/mil-005-collision-levelup.md
+[QC-PY-001]: ../../../framework/qc/code/qc-programming-python.md

src/car_manager.py

@@ -5,8 +5,10 @@
 import random
 from collections.abc import Callable
 from turtle import Turtle
+from typing import Protocol
 
 from car_shape import shape_name
+from collision import is_colliding
 from constants import (
     CAR_REMOVE_X,
     CAR_START_X,
@@ -18,6 +20,18 @@ from constants import (
 )
 
 
+class HasPosition(Protocol):
+    """@brief Anything with a position, such as a turtle."""
+
+    def xcor(self) -> float:
+        """@brief X coordinate."""
+        ...
+
+    def ycor(self) -> float:
+        """@brief Y coordinate."""
+        ...
+
+
 class CarManager:
     """@brief Keeps the cars of the road: creates, moves and removes them."""
 
@@ -54,6 +68,17 @@ class CarManager:
             car.hideturtle()
             self.all_cars.remove(car)
 
+    def is_hit(self, player: HasPosition) -> bool:
+        """@brief Tell whether any car collides with the player.
+
+        @param player Anything exposing xcor and ycor.
+        @return True when a car overlaps the player.
+        """
+        return any(
+            is_colliding(player.xcor(), player.ycor(), car.xcor(), car.ycor())
+            for car in self.all_cars
+        )
+
     def level_up(self) -> None:
         """@brief Make the cars faster."""
         self.move_distance += MOVE_INCREMENT

src/collision.py

@@ -0,0 +1,21 @@
+"""@file collision.py
+@brief The collision rule between the player and a car, free of any window.
+"""
+
+from constants import CAR_HEIGHT, CAR_LENGTH, PLAYER_HALF_SIZE
+
+
+def is_colliding(player_x: float, player_y: float, car_x: float, car_y: float) -> bool:
+    """@brief Tell whether the player's square overlaps the car's rectangle.
+
+    Touching edges is not a collision.
+
+    @param player_x X coordinate of the player's centre.
+    @param player_y Y coordinate of the player's centre.
+    @param car_x X coordinate of the car's centre.
+    @param car_y Y coordinate of the car's centre.
+    @return True when the two shapes overlap.
+    """
+    is_overlapping_x = abs(player_x - car_x) < CAR_LENGTH / 2 + PLAYER_HALF_SIZE
+    is_overlapping_y = abs(player_y - car_y) < CAR_HEIGHT / 2 + PLAYER_HALF_SIZE
+    return is_overlapping_x and is_overlapping_y

src/main.py

@@ -31,6 +31,15 @@ def main() -> None:
         car_manager.create_cars()
         car_manager.move_cars()
 
+        if car_manager.is_hit(player):
+            game_is_on = False
+
+        if player.is_at_finish_line():
+            player.go_to_start()
+            car_manager.level_up()
+
+    screen.exitonclick()
+
 
 if __name__ == "__main__":
     main()

src/player.py

@@ -4,7 +4,7 @@
 
 from turtle import Turtle
 
-from constants import MOVE_DISTANCE, STARTING_POSITION
+from constants import FINISH_LINE_Y, MOVE_DISTANCE, STARTING_POSITION
 
 
 class Player(Turtle):
@@ -15,8 +15,19 @@ class Player(Turtle):
         super().__init__(shape="turtle")
         self.penup()
         self.setheading(90)
-        self.goto(STARTING_POSITION)
+        self.go_to_start()
 
     def go_up(self) -> None:
         """@brief Move one step north."""
         self.forward(MOVE_DISTANCE)
+
+    def is_at_finish_line(self) -> bool:
+        """@brief Tell whether the player has crossed the road.
+
+        @return True when the player is above the finish line.
+        """
+        return self.ycor() > FINISH_LINE_Y
+
+    def go_to_start(self) -> None:
+        """@brief Put the player back at the starting position."""
+        self.goto(STARTING_POSITION)

tests/test_car_manager.py

@@ -36,6 +36,9 @@ class FakeCar:
     def xcor(self) -> float:
         return self.x
 
+    def ycor(self) -> float:
+        return self.y
+
     def setx(self, x: float) -> None:
         self.x = x
 
@@ -99,6 +102,37 @@ def test_cars_past_the_left_edge_are_removed() -> None:
     assert manager.all_cars == [] and car.hidden
 
 
+class FakePlayer:
+    """Stands in for the player turtle."""
+
+    def __init__(self, x: float, y: float) -> None:
+        self.x, self.y = x, y
+
+    def xcor(self) -> float:
+        return self.x
+
+    def ycor(self) -> float:
+        return self.y
+
+
+def test_is_hit_when_a_car_overlaps_the_player() -> None:
+    manager = make_manager()
+    manager.create_cars()
+    car = manager.all_cars[0]
+    assert manager.is_hit(FakePlayer(car.x, car.y))
+
+
+def test_is_not_hit_when_cars_are_far_away() -> None:
+    manager = make_manager()
+    manager.create_cars()
+    car = manager.all_cars[0]
+    assert not manager.is_hit(FakePlayer(car.x - 200, car.y))
+
+
+def test_is_not_hit_when_there_are_no_cars() -> None:
+    assert not make_manager().is_hit(FakePlayer(0, 0))
+
+
 def test_level_up_increases_speed() -> None:
     manager = make_manager()
     manager.level_up()

tests/test_collision.py

@@ -0,0 +1,31 @@
+"""Tests for the pure collision rule."""
+
+from collision import is_colliding
+from constants import CAR_HEIGHT, CAR_LENGTH, PLAYER_HALF_SIZE
+
+REACH_X = CAR_LENGTH / 2 + PLAYER_HALF_SIZE
+REACH_Y = CAR_HEIGHT / 2 + PLAYER_HALF_SIZE
+
+
+def test_hit_when_player_overlaps_car() -> None:
+    assert is_colliding(5, 3, 0, 0)
+
+
+def test_no_hit_when_beyond_car_half_length_horizontally() -> None:
+    assert not is_colliding(REACH_X + 1, 0, 0, 0)
+
+
+def test_no_hit_when_a_lane_away_vertically() -> None:
+    assert not is_colliding(0, CAR_HEIGHT * 2, 0, 0)
+
+
+def test_no_hit_when_exactly_at_horizontal_boundary() -> None:
+    assert not is_colliding(REACH_X, 0, 0, 0)
+
+
+def test_no_hit_when_exactly_at_vertical_boundary() -> None:
+    assert not is_colliding(0, REACH_Y, 0, 0)
+
+
+def test_hit_just_inside_the_boundary() -> None:
+    assert is_colliding(REACH_X - 1, REACH_Y - 1, 0, 0)

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()