Automate python testing with CircleCI

What is CI

Continuous integration, CI (English: continuous integration), is the merging of working copies of all developers into a shared mainline several times a day. (wikipedia)

It's a mystery to hear integration, but it's basically a development method that automates build, test, and deploy tasks. By introducing CI, it seems that software development can be carried out efficiently.

In this article, we aim to build an environment where CircleCI and Github are linked so that tests are automatically executed when the python development code is pushed. Reference article: https://scotch.io/tutorials/continuous-integration-with-python-and-circle-ci

tool

Register an account and link CircleCI and Github.

• GitHub
• Circle CI

Environmental setting

• Python: 3.7

Creating a project

Create a project file as shown below.

Folder structure

+-- pyhton-ci
    +-- src
    |   +-- match.py
    +-- tests
        +-- math-test.py

src/math.py

def addition(value1, value2):
    if not isinstance(value1, int) and not isinstance(value2, int):
        return 'Invalid input'
    else:
        return value1 + value2

tests/math-test.py

import unittest
from src.math import addition

class MathTest(unittest.TestCase):
    def test_addition(self):
        actual = addition(3,4)
        expected = 8 #Matches the execution result
        self.assertEqual(actual, expected)

Run unittest from the command line

nosetests tests/math-test.py 

ʻAssertionError: 7! = 8` is output, and confirm that the test has failed.

Preparing files for CircleCI

Add the following files to your project

+-- pyhton-ci
    +-- src
    |   +-- match.py
    +-- tests
    |   +-- math-test.py
    +-- requirements.txt
    +-- .circleci
        +-- config.yml

Dependency management file

requirements.txt

nose==1.3.7

circleCI configuration file

version: 2
jobs:
  build:
    working_directoyr: ~/python-ci
    docker:
      - image: circleci/python:3.6.4
    steps:
      - checkout
      - run:
          command: sudo pip install -r requirements.txt
      - run:
          command: nosetests tests/math-test.py

Create a new Github repository and push the entire project folder to the develop branch.

git push origin develop

CircleCI settings

On the CircleCI screen, select Projects-> Repository-> Start Building-> Add Manually-> Start Building And select

The test results are displayed on the Pipelines screen.

Enable Github Status Checks

Select Settings-> Branches tab-> Add rule in the Github repository

Enter develop (development branch name) in the Branch name pattern

Require status checks to pass before merging Require branches to be up to date before merging Check the box.

Cut the working branch appropriately and send a pull request to develop. Then, the following status check is performed on the pull request screen.

Modify the test code as below and push again.

math-test.py

class MathTest(unittest.TestCase):
    def test_addition(self):
        actual = addition(3,4)
        expected = 7 #Matches the execution result
        self.assertEqual(actual, expected)

I was able to confirm that it passed the test!