Test Driven Development

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This repo serves as a simplified example to unit test with pytest and basic CI/CD workflows with github actions. It is by no means a comprehensive or fully correct implementation but serves as a starting point from my point of view.

Prerequisites

Before starting it is recommended that flake8 and black is installed and set up. For this program we allow 120 characters per line and both flake8 and black are setup as such globally.

it is assumed the python, black and flake8 addons are installed.

To access these settings on VS-code press ctrl+,:

Black

For Black, under the user tab searck Black-formatter:Args. Press Add Item and enter --line-length and press OK. Then Press Add Item again and enter 120 followed by pressing OK.

flake8

For flake8, similarly search Flake8 and scroll down until you reack Flake8:Args. Press Add Item and enter --max-line-length then press OK. Press Add Item again and enter 120 then press OK.

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CI/CD Github Actions

Linter

The linter action is setup to run in the file .github/workflows/linter.yml which looks like:

# This workflow executes several linters on changed files based on languages used in your code base whenever
# you push a code or open a pull request.
#
# You can adjust the behavior by modifying this file.
# For more information, see:
# https://github.com/github/super-linter
name: Lint Code Base

on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]
jobs:
  run-lint:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
        with:
          # Full git history is needed to get a proper list of changed files within `super-linter`
          fetch-depth: 0

      - name: Lint Code Base
        uses: github/super-linter@v4
        env:
          VALIDATE_ALL_CODEBASE: true
          VALIDATE_PYTHON_FLAKE8: true
          DEFAULT_BRANCH: "main"
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

It uses the .flake8 file to adjust the parameters:

[flake8]
max-line-length = 120

If the file is not linted correctly this action will fail.

Unit tests

The unit test CI/CD action is found in .github/workflows/unittest.yml and looks like:

name: Run Unit Test via Pytest  
  
on: [push]  
  
jobs:  
  build:  
    runs-on: ubuntu-latest  
    strategy:  
      matrix:  
        python-version: ["3.11"]  
  
    steps:  
      - uses: actions/checkout@v3  
      - name: Set up Python ${{ matrix.python-version }}  
        uses: actions/setup-python@v4  
        with:  
          python-version: ${{ matrix.python-version }}  
      - name: Install dependencies  
        run: |  
          python -m pip install --upgrade pip
          python -m pip install coverage pytest
          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi   
      - name: Test with pytest  
        run: |  
          coverage run -m pytest  -v -s  
      - name: Generate Coverage Report  
        run: |  
          coverage report -m

This pulls the code and runs the unit tests using pytest. If any test case fails the action will fail.

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Unit Test Files

Unit test files have the prefix *_test.py e.g. calculations_test.py. The pytest package should be consulted for how to utilise them.