Running PyTest in GitHub Actions - Build an Automation Script

Automate running PyTest tests in GitHub Actions

Preconditions (2)

Step 1: Create a .github/workflows/python-test.yml file in the repository

Step 2: Define a workflow that triggers on push and pull request events

Step 3: Set up a job that runs on ubuntu-latest

Step 4: Add steps to check out the repository code

Step 5: Add a step to set up Python 3.12

Step 6: Add a step to install dependencies from requirements.txt

Step 7: Add a step to run pytest command

Step 8: Push the workflow file to the repository

✅ Expected Result: GitHub Actions runs the workflow on push or pull request, installs dependencies, runs pytest tests, and reports test results as pass or fail in the Actions tab

Automation Requirements - GitHub Actions YAML workflow

Assertions Needed:

Verify workflow triggers on push and pull request

Verify Python 3.12 is used

Verify dependencies are installed

Verify pytest runs and completes successfully

Verify test results are reported in GitHub Actions

Best Practices:

Use official actions like actions/checkout and actions/setup-python

Use explicit Python version 3.12

Cache dependencies if possible

Keep workflow steps clear and simple

Use separate steps for install and test

Automated Solution

PyTest

name: Python PyTest CI

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  test:
    runs-on: ubuntu-latest

    steps:
    - name: Check out repository code
      uses: actions/checkout@v3

    - name: Set up Python 3.12
      uses: actions/setup-python@v4
      with:
        python-version: '3.12'

    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        pip install -r requirements.txt

    - name: Run PyTest
      run: |
        pytest

This GitHub Actions workflow is named 'Python PyTest CI'. It triggers on pushes and pull requests to the main branch.

The job runs on the latest Ubuntu runner.

First, it checks out the repository code using the official actions/checkout@v3 action.

Then it sets up Python 3.12 explicitly using actions/setup-python@v4.

Next, it installs dependencies from requirements.txt using pip.

Finally, it runs pytest to execute the tests.

This setup ensures tests run automatically on GitHub servers and results show in the Actions tab.

Common Mistakes - 5 Pitfalls

Not specifying the Python version explicitly

Not installing dependencies before running tests

Running pytest without checking out the code

Using an outdated or incorrect action version

{'mistake': 'Not triggering workflow on pull requests', 'why_bad': "Tests won't run on code changes from forks or branches before merging.", 'correct_approach': 'Include pull_request trigger to test all proposed changes.'}

Bonus Challenge

Now add caching of pip dependencies to speed up workflow runs

Show Hint

Practice

1. What is the main purpose of running pytest in a GitHub Actions workflow?

easy

A. To automatically test code changes and catch errors early

B. To deploy the application to production

C. To create a backup of the repository

D. To format the code automatically

Solution

1. Step 1: Understand pytest's role in GitHub Actions CI

   PyTest is a testing tool that checks if code works correctly. GitHub Actions runs tests automatically on code changes to catch errors early.

2. Final Answer:

   To automatically test code changes and catch errors early -> Option A

3. Quick Check:

   PyTest in GitHub Actions = automatic testing [OK]

Hint: PyTest in GitHub Actions runs tests automatically [OK]

Common Mistakes:

• Confusing testing with deployment
• Thinking PyTest formats code
• Assuming it creates backups

2. Which of the following is the correct step to install PyTest in a GitHub Actions workflow YAML file?

easy

A. run: apt-get install pytest

B. run: npm install pytest

C. run: pip install pytest

D. run: brew install pytest

Solution

1. Step 1: Identify the package manager and correct install command for PyTest

   PyTest is a Python package installed using pip. The correct command is run: pip install pytest.

2. Final Answer:

   run: pip install pytest -> Option C

3. Quick Check:

   Python packages use pip install [OK]

Hint: Use pip to install Python packages like PyTest [OK]

Common Mistakes:

• Using npm which is for JavaScript
• Using apt-get or brew which are system package managers
• Missing the pip command

3. Given this GitHub Actions step in a workflow YAML file:

  - name: Run tests
    run: pytest tests/

What will happen when this step runs?

medium

A. PyTest will deploy the tests to a server

B. PyTest will install dependencies before running tests

C. PyTest will create a test report file automatically

D. PyTest will run all tests inside the tests/ directory

Solution

1. Step 1: Analyze the pytest tests/ command and default behavior

   pytest tests/ runs all test files inside the tests/ folder by default but does not install dependencies or deploy code.

2. Final Answer:

   PyTest will run all tests inside the tests/ directory -> Option D

3. Quick Check:

   pytest tests/ runs tests in tests/ folder [OK]

Hint: pytest <folder> runs tests in that folder [OK]

Common Mistakes:

• Thinking PyTest installs dependencies
• Assuming PyTest deploys code
• Expecting automatic report file creation

4. You wrote this GitHub Actions step:

- name: Run tests
  run: py.test

But the workflow fails with "command not found" error. What is the likely cause?

medium

A. The command should be pytest not py.test

B. PyTest is not installed before running the tests

C. The tests directory is missing

D. GitHub Actions does not support running tests

Solution

1. Step 1: Diagnose the command not found error for py.test

   PyTest must be installed first; both pytest and py.test work if installed.

2. Final Answer:

   PyTest is not installed before running the tests -> Option B

3. Quick Check:

   Install PyTest before running tests [OK]

Hint: Always install PyTest before running it in workflow [OK]

Common Mistakes:

• Assuming command spelling is wrong
• Ignoring PyTest installation step
• Blaming GitHub Actions for test failures

5. You want to create a GitHub Actions workflow that runs PyTest on Python 3.10 and 3.11 versions. Which YAML snippet correctly sets up the Python versions and runs PyTest?

hard

A. jobs:
test:
runs-on: ubuntu-latest
strategy:
matrix:
python-version: [3.10, 3.11]
steps:
- uses: actions/checkout@v3
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: ${{ matrix.python-version }}
- name: Install dependencies
run: pip install pytest
- name: Run tests
run: pytest

B. jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: 3.10
- name: Install dependencies
run: pip install pytest
- name: Run tests
run: pytest
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: 3.11
- name: Run tests
run: pytest

C. jobs:
test:
runs-on: ubuntu-latest
strategy:
matrix:
python-version: [3.10, 3.11]
steps:
- uses: actions/checkout@v3
- name: Install dependencies
run: pip install pytest
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: ${{ matrix.python-version }}
- name: Run tests
run: pytest

D. jobs:
test:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: 3.10
- name: Run tests
run: pytest

Solution

1. Step 1: Identify YAML with matrix strategy and correct step order for multi-version testing

   Use strategy.matrix to run on 3.10/3.11; checkout, then setup Python with ${{ matrix.python-version }}, install pytest, run tests.

2. Final Answer:

   YAML snippet with matrix strategy and correct step order -> Option A

3. Quick Check:

   Matrix + setup-python + install + run = jobs: test: runs-on: ubuntu-latest strategy: matrix: python-version: [3.10, 3.11] steps: - uses: actions/checkout@v3 - name: Set up Python uses: actions/setup-python@v4 with: python-version: ${{ matrix.python-version }} - name: Install dependencies run: pip install pytest - name: Run tests run: pytest [OK]

Hint: Use matrix for versions, setup-python before install and test [OK]

Common Mistakes:

• Not using matrix for multiple versions
• Installing PyTest before setting Python version
• Repeating setup-python steps instead of matrix