Class 3 — Save points

Block 1 · Theory · 2026-09-15

What you need

• Last week's folder, with your bug #1 fix and your ONBOARDING.md answers.
• A GitHub account (university email). No account yet? Create one at github.com now.
• GitHub Desktop, installed and signed in. Windows: it installs git for you, nothing else needed.
• uv from last week. Tests run with uv run pytest tests/test_bugs.py; no install step, pytest is in the project.

In class

Git in four words: repo, commit, branch, push. Save points for code, all through GitHub Desktop buttons, no terminal.

1. Your folder becomes a repo. GitHub Desktop → Add local repository → Create a repository here → Publish repository, name it splitit or tiny-crm, keep it private. Last week's fix is your first commit. One repo per person.
2. Bug #0, one line, one commit. Read the report, run the red test, follow the click, fix, green, commit, push. Live on SplitIt first, then on your repo.
3. A spec from the PM. What specs/feature-1 asks for, and the tests in tests/test_feature_1.py that say when it is done. Run them before you build: four red tests is your to-do list.
4. Feature 1, live. Branch → red tests → prompt Codex with the spec → read the diff → green → check it in the app → commit, push, pull request, merge.

Your turn

• SplitIt: bug issues/000-group-title.md, then specs/feature-1-balances.md on a branch called feature-1-balances.
• Tiny CRM: bug issues/000-lead-count.md, then fix issues/002-overdue-order.md (the spec says so at the top), then specs/feature-1-overdue.md on a branch called feature-1-overdue.

Copies of the bug reports and specs are in the materials below; the ones that count are the files inside your own repo.

When git is confusing

• Wrong branch? Current branch → switch. GitHub Desktop offers to bring your changes along; say yes.
• Broke a file? Right-click it in GitHub Desktop → Discard changes.
• Broke the data? uv run python seed.py, same as last week.
• An error you don't understand? Screenshot it, ask Codex to explain it, then ask us.

Homework — before Class 4

1. Finish feature 1 on its branch: tests green, merged, pushed.
2. Your repo is the one that counts now. Not the ZIP, not the folder. Push before you close the laptop, every time.
3. Read specs/feature-2 and issues/002 in your repo. That is Class 4.

Nothing to hand in. In Class 4 the TA will ask to see your GitHub page: the feature-1 branch and a merged commit.