Add the shapes challenge to the command line

turtle-challenges shapes draws the polygons. The argument parsing tests already
cover every registered name.

Task: MIL-003#6

src/turtle_challenges/cli.py

@@ -10,10 +10,12 @@ from functools import partial
 from turtle_challenges.constants import (
     CHALLENGE_DASHED_LINE,
     CHALLENGE_NAMES,
+    CHALLENGE_SHAPES,
     CHALLENGE_SQUARE,
 )
 from turtle_challenges.dashed_line import draw_dashed_line
 from turtle_challenges.pen import Pen
+from turtle_challenges.shapes import draw_shapes
 from turtle_challenges.square import draw_square
 from turtle_challenges.window import (
     TurtleUnavailableError,
@@ -52,6 +54,7 @@ def build_challenges(pen: Pen) -> dict[str, Callable[[], None]]:
     return {
         CHALLENGE_SQUARE: partial(draw_square, pen),
         CHALLENGE_DASHED_LINE: partial(draw_dashed_line, pen),
+        CHALLENGE_SHAPES: partial(draw_shapes, pen),
     }
 
 

src/turtle_challenges/constants.py

@@ -68,8 +68,12 @@ CHALLENGE_SQUARE = "square"
 ## Command line name of challenge 2.
 CHALLENGE_DASHED_LINE = "dashed-line"
 
+## Command line name of challenge 3.
+CHALLENGE_SHAPES = "shapes"
+
 ## Names of the challenges on the command line, in the order of the course.
 CHALLENGE_NAMES: tuple[str, ...] = (
     CHALLENGE_SQUARE,
     CHALLENGE_DASHED_LINE,
+    CHALLENGE_SHAPES,
 )