023-turtle-crossing/docs/business-case.md

Business Case

Metadata

Key	Value
ID	BC-001
CrossReference	SA-001, PP-001
Language	en
Domain	it

Version History

Date	Status	Author	Reviewer	Change	Commit
2026-10-13	Accepted	Jens Tirsvad Nielsen	AI as stand-in for S01	Initial version	93d8321

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Executive Summary

Day 23 of Udemy's "100 Days of Code: The Complete Python Pro Bootcamp" is the second capstone: a Turtle Crossing game in the style of Crossy Road. The player steers a turtle north across a multi-lane road of randomly generated cars; each crossing raises the level and the car speed, and a collision ends the game. This project delivers the game as a small, readable, tested Python repository with no runtime dependencies, so that course participants can run and compare it and GitHub visitors can browse it for ideas.

Methodological and Standards Foundation

• Object-oriented design with one class per concern (Player, CarManager, Scoreboard), using the assignment's names.
• Quality characteristics follow ISO/IEC 25010:2023, as the QC checklists of the SQA framework tag them.
• Source is documented with Doxygen comments and built with a Doxyfile.
• Work follows the software quality assurance (SQA) and quality control (QC) framework mounted at framework/: plan first, review each artifact, one pull request per milestone.

Problem Statement

The course supplies four stub files and a video walkthrough, but no repository that a participant can clone, run, test and read. Solutions shared between coursists are single files without tests, run instructions or a statement of the Python version they need, and cars are drawn as plain colour blocks.

Business Opportunity

A well-structured reference solution gives S02 a runnable comparison point and gives S03 a clear example of a small Python project with tests, continuous integration (CI), documentation and a multilingual wiki, at no dependency cost.

Objectives

1. Deliver the game behaviour of the Day 23 assignment at Normal difficulty (all steps): forward-only turtle, random cars moving left, level-up with speed increase, collision stop, scoreboard and GAME OVER.
2. Draw each car so it reads as a car (body, cabin, wheels), not a colour block, while keeping the 20 x 40 px footprint the assignment specifies.
3. Provide src/, tests/ and docs/ with pytest tests for the game logic and no runtime dependencies beyond the Python standard library.
4. Provide a README from the agreed template, a local .venv guide, a Doxyfile, CI and a wiki in English, Danish and Bahasa Malaysia.
5. Publish the repository with a description and topics.

Scope

In Scope

• Player, car manager and scoreboard classes, constants.py, main.py.
• Car appearance drawn with the standard turtle module only.
• Unit tests for the logic that does not need a display.
• pyproject.toml (Python 3.13 or newer), Python .gitignore, Doxygen comments and Doxyfile.
• README, CI workflow, wiki pages in en, da and ms.
• Repository description and topics on the git host.

Out of Scope

• Sound, images, sprite files or any third-party package at runtime.
• Menus, difficulty selection, high-score persistence, networking.
• Packaging for PyPI.
• Re-implementing the Hard and Expert course variants.

Expected Benefits

Tangible Benefits

• A cloneable repository that runs with one command after the venv is set up.
• A passing automated test suite and a CI run on every pull request.
• Generated source documentation for the three classes.

Intangible Benefits

• A readable example S02 can compare their own solution against.
• A documented course portfolio item for S01 with a visible review trail.

Strategic Alignment

This is one project in the 100 Days of Code portfolio. It demonstrates the same planning, review and pull-request discipline across the whole series.

Success Criteria

#	Criterion	Target	Measure
1	Game plays as the assignment describes	All five Step 2 behaviours work	Manual play-through checklist in the final milestone
2	Cars look like cars	Each car shows a body, cabin and two wheels, 40 x 20 px	Visual check in the Cars milestone
3	Tests pass	100 % of tests pass on Python 3.13	pytest exit code 0 locally and in CI
4	No runtime dependencies	Zero entries under dependencies	pyproject.toml inspection
5	Run instructions work	A fresh clone runs following the README on Windows, Linux and macOS sections	S01 follows the README on a clean clone
6	Wiki in three languages	Every wiki page exists in en, da, ms	File listing of the wiki
7	Repository metadata	Description and at least 5 topics set	Repository page

Risks

Risk	Impact	Mitigation
Turtle needs a display, so CI and tests cannot open a window	Tests cannot cover rendering	Keep game logic free of the screen where possible; test it against a stub; verify rendering manually
Custom car shape renders differently across platforms	Cars look wrong for some viewers	Use turtle.register_shape with polygons only; check on Windows first and note limits in the README
Python 3.13 tkinter missing on some Linux installs	Participants cannot run the game	Document python3-tk in the Linux Debian section
Tokens in .env end up in the repository	Credential leak	.env in .gitignore before the first commit that adds files; the file is never read by project code
Scope creep from "nice to have" features	Delay	Out of Scope list; changes need a Business Case amendment

Assumptions

• S01 is Product Owner, developer and reviewer; reviews are not independent (supervised mode).
• The idea is a hunch, not validated by behaviour, and is cheap to build, so no riskiest-assumption test is run.
• S01 can reach S02 and S03 through the git host and the course forum.
• The git host git.tirsystem.com is available for the repository and wiki.
• S01 stated no deadline; the plan assumes two weeks (see PP-001 Open Issues).

Constraints

• Python 3.13 or newer, a local .venv, pytest for tests.
• Constants live in constants.py; configuration lives in pyproject.toml.
• Layout is src/, tests/ and docs/.
• Only the standard library at runtime.

Cost–Benefit Assessment

Qualitative: the project is a learning exercise with no budget.

Costs	Benefits
S01's time: about two weeks of evening work	Portfolio item, a reusable project template, a shareable solution
Review effort (S01 reviews own work)	Documented planning and review trail

Stakeholders

Stakeholder ID (SA)	Interest in this project
S01	Product Owner, developer and reviewer; wants a finished, well-planned portfolio piece
S02	Udemy coursists; want readable, runnable code with the assignment's names and run instructions
S03	GitHub viewers; want a clear description, topics and README, and no runtime dependencies

Recommendation

Proceed — the scope is small, cheap and fully specified by the course, and it serves all three stakeholders.

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