GitHub Actions Workshop

This is a hands-on practice session. You already know the theory — let's build it.

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What's in this repo

File	Description
main.py	A simple Calculator class with four operations
test_main.py	Unit tests for the Calculator class

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Part 1 — Fork and clone

1. Click Fork at the top-right of this page.
2. Clone your fork locally:

git clone https://github.com/<your-username>/<repo-name>.git
cd <repo-name>

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Part 2 — Run the tests locally

python -m unittest test_main.py -v

Expected output:

test_add (test_main.TestCalculator) ... ok
test_divide (test_main.TestCalculator) ... ok
test_divide_by_zero (test_main.TestCalculator) ... ok
test_multiply (test_main.TestCalculator) ... ok
test_subtract (test_main.TestCalculator) ... ok

----------------------------------------------------------------------
Ran 5 tests in 0.001s

OK

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Part 3 — Break a test

In main.py, change add to subtract:

def add(self, a, b):
    return a - b   # bug

Run the tests again and observe the failure. Then revert:

def add(self, a, b):
    return a + b   # fixed

Confirm tests pass before moving on.

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Part 4 — Set up GitHub Actions (follow along with instructor)

Step 1 — Create the workflow folder

mkdir -p .github/workflows

Step 2 — Create the workflow file

Create .github/workflows/python-tests.yml and write it together with your instructor.

Step 3 — Push and watch it run

git add .github/workflows/python-tests.yml
git commit -m "Add GitHub Actions workflow to run tests"
git push origin main

Open the Actions tab on your GitHub repo and watch the workflow run.

Step 4 — Confirm it catches a bug

Push the bug from Part 3, watch the workflow go red, then fix and push again.

# introduce bug
git add main.py
git commit -m "Introduce bug"
git push origin main

# fix bug
git add main.py
git commit -m "Fix add method"
git push origin main