Add the CarManager and car-shaped cars

Task: MIL-004#1
Task: MIL-004#2
Task: MIL-004#3
Task: MIL-004#4

tests/test_car_shape.py

@@ -0,0 +1,28 @@
+"""Tests for the car drawing."""
+
+from car_shape import car_components, register_car_shapes, shape_name
+from constants import CAR_HEIGHT, CAR_LENGTH, COLORS
+
+
+def test_car_fits_the_footprint() -> None:
+    points = [p for polygon, _, _ in car_components("red") for p in polygon]
+    assert all(abs(x) <= CAR_LENGTH / 2 for x, _ in points)
+    assert all(abs(y) <= CAR_HEIGHT / 2 for _, y in points)
+
+
+def test_car_is_more_than_a_colour_block() -> None:
+    components = car_components("red")
+    fills = [fill for _, fill, _ in components]
+    assert fills.count("black") == 2  # two wheels
+    assert "light sky blue" in fills  # windows
+    assert len(components) >= 5
+
+
+def test_body_and_cabin_use_the_car_colour() -> None:
+    fills = [fill for _, fill, _ in car_components("green")]
+    assert fills.count("green") == 2
+
+
+def test_register_car_shapes_adds_one_shape_per_colour(screen) -> None:
+    register_car_shapes(screen)
+    assert all(shape_name(color) in screen.getshapes() for color in COLORS)