Pytest with eric

Notes from pytest with eric

This is a collection of notes from pytest with eric.

Take a look here: https://pytest-with-eric.com/

Basic concepts

• Maximizing Quality - A Comprehensive Look at Testing in Software Development 1
  • different kinds of tests
• How To Test Python Exception Handling Using Pytest Assert (A Simple Guide)
  • assert is a great way to write a basic test suite

Running tests

• How To Run A Single Test In Pytest (Using CLI And Markers) - Basic usages
• How Pytest Fixtures Can Help You Write More Readable And Efficient Tests - Overview on fixtures
• What Are Pytest Fixture Scopes (How To Choose The Best Scope For Your Test) - Scopes of fixtures
• A Step-by-Step Guide To Using Pytest Fixtures With Arguments - Parametrize
• How to Auto-Request Pytest Fixtures Using Autouse - Autouse
• How To Access Test Details With Pytest Request Fixture - Special Request fixture
  • Yield vs Return
    • Use return when you want to send back one final result and stop the function.
    • Use yield when you want to produce a series of values, one at a time, without losing the function’s current state. This is common when working with large datasets or when the next value depends on the previous ones.
• What is Setup and Teardown in Pytest (Importance of a Clean Test Environment) - Yield
• What Is Pytest Caplog (Everything You Need To Know) - Log
  • Caplog has different log levels, use the more appropriate one
• How To Manage Temporary Files with Pytest tmp_path - Temp files
  • Pytest will take care of temp files by itself, trying to be the more platform-agnostic ever
• How to Effortlessly Generate Unit Test Cases with Pytest Parameterized Tests - Unit test generated test cases
  • Use range, parametrize and fixtures
• [[A Beginner’s Guide To pytest_generate_tests]] - Pytest generate tests
  • We can use parametrize instead of pytest_generate_tests

Mocking

• Common Mocking Problems & How To Avoid Them (+ Best Practices)
  • when to use mocking
• Mocking vs Patching in short
  • Mocking = create a fake version you can play with.
  • Patching = temporarily cover up a real thing with a fake one during the test.
• Mocking Vs. Patching (A Quick Guide For Beginners)
• How To Mock In Pytest (A Comprehensive Guide)
  • Mocking is used when you want to test the functionality as a system you need to test the real connections e.g. your API can connect to the database or external API.
• What Are Pytest Mock Assert Called Methods and How To Leverage Them
  • Magic Mock vs Mock: one is special and it has all the capabilities of a regular Mock, but with the addition of most of the “magic” or “dunder” methods pre-created.
    • If you need a mock object to emulate special methods or operations, using MagicMock is often more convenient than using a basic Mock.
• Monkeypatch with 2 Code Examples
  • modify a code snippet temporarily “on-the-fly”.
    • IMPORTANT: it is temporary, once you are done it’s gone.
    • def say_hello(): return “hello”
    • say_hello = lambda: “goodnight”
    • print(say_hello) → goodnight
• How To Test Raised Exceptions with Pytest MagicMock (Advanced Guide)
  • How to test exceptions
  • Again, Mock vs Magic Mock vs Patch
• How To Return Multiple Values From Pytest Mock (Practical Guide)
  • side_effect: if side_effect = [1, 2, 3], the mock will return 1 the first time it’s called, 2 the next time, and 3 after that.
• Mock Celery

Configuration & Environment Variables

• How To Overwrite Dynaconf Variables For Testing In Python
  • solve the problem of switching .env files in dev and prod, particularly useful!
• Pytest Conftest With Best Practices And Real Examples
  • nothing so relevant
• [[What Is pytest.ini And How To Save Time Using Pytest Config]]
  • set log level, input output log, required plugins
  • see also https://pytest-with-eric.com/pytest-best-practices/pytest-logging/
• Pytest Config Files - A Practical Guide To Good Config Management
  • pytest vs pyproject vs setup.cfg vs tox.ini
• How To Ignore Warnings In Pytest (With Examples)
  • just use the appropriate flag
  • you can always filter them
• 3 Simple Ways To Ignore Test Directories in Pytest
  • CLI, pytest.ini and marker (xskip, xfail…)
• How To Use Pytest With Command Line Options (Easy To Follow Guide)
  • you can define custom CLI command to be executed with pytest (example: a pwd generator)
• 4 Proven Ways To Define Pytest PythonPath and Avoid Module Import Errors
  • nothing so relevant
• 3 Simple Ways To Define Environment Variables In Pytest
  • env_vars in test
  • python-dotenv or pytest-dotenv
  • pytest-env

Markers

Ultimate Guide To Pytest Markers And Good Test Management

• common markers, what they are, the most common ones

Property Based Testing

How to Use Hypothesis and Pytest for Robust Property-Based Testing in Python

• a new way to generate test cases, based on properties / property-based

Async Testing

A Practical Guide To Async Testing With Pytest-Asyncio

• just use the proper fixture for async tasks

FastAPI // TODO

• https://pytest-with-eric.com/#FastAPI-Testing

• https://pytest-with-eric.com/api-testing/pytest-api-testing-1/

• https://pytest-with-eric.com/api-testing/pytest-api-testing-2/

• https://pytest-with-eric.com/pytest-advanced/pytest-fastapi-testing/

• Django Testing

https://pytest-with-eric.com/pytest-advanced/pytest-django-restapi-testing/

• a practical hands-on, not much to say

External/3rd Party API Call Testing

• How To Write Tests For External (3rd Party) API Calls with Pytest
  • different ways to test API calls (examples: sandbox)
• Python REST API Unit Testing for External APIs
  • test external API using mocking and patches

Database Testing

How To Test Database Transactions With Pytest And SQLModel

• we can use pytest for manual creating objects and test with sqalchemy if it’s what we need

Web Automation Testing

• How To Use Pytest With Selenium For Web Automation Testing
  • basically browse the page throught selenium webdriver and look for specific elements if they contains specific values
• Test Automation Made Easy with Pytest and Playwright
  • PlayWright it’s slightly more complicate than Selenium but it’s newer
• How To Create Interactive Test Reports with Pytest and Allure
  • it is possible to create test reports with Allure, a platform that could be setup in a machine and used to interact with pytest results

CI/CD Pipelines

• https://pytest-with-eric.com/integrations/pytest-github-actions/
  • how to create a github actions and run pytest in a nutshell
• How To Test And Build Python Packages With Pytest, Tox And Poetry
  • poetry dependencies management

Plugins and Integrations

• 8 Useful Pytest Plugins To Make Your Python Unit Tests Easier, Faster and Prettier
  • pytest-cov
    • code coverage reporting for Python projects.
  • pytest-mock
    • simple but powerful mocking functionality
  • pytest-xdist
    • enables parallel testing for Python projects
  • pytest-timeout
    • provides a simple way to set timeouts for your test functions
  • pytest-asyncio
    • test async code
  • pytest-sugar
    • enhances the output of Pytest’s test execution progress by providing a more detailed and visually appealing representation of test results
  • pytest-html
    • generates HTML reports for your test results
  • pytest-profiling
    • provides easy profiling of your code during test execution
• How To Create Custom HTML Test Reports With pytest-html
  • --html option for beautiful reports > you can even customize title, colors and so on
• Parallel Testing Made Easy With pytest-xdist
  • you can specify number of workers with -n
• A Simple Guide To Controlling Time in Pytest Using Freezegun
  • freezegun: “run as date”, mocking a specific datetime
• How To Measure And Improve Code Efficiency with Pytest Benchmark (The Ultimate Guide)
  • use pytest-benchmark plugin
• How To Avoid Hanging Tests Using Pytest Timeout (And Save Compute Resource)
• An Ultimate Guide To Using Pytest Skip Test And XFail - With Examples
  • already covered
• Save Money On You CI/CD Pipelines Using Pytest Parallel (with Example)
  • use pytest-xdist and specify number of workers with -n auto
• A Comprehensive Guide to Pytest Approx for Accurate Numeric Testing

Coverage

• 3 Simple Ways To Omit Subfolders From Python Coverage Reports
  • Configuring .coveragerc ⇒ [run] omit = */migrations/*
  • Configuring pyproject.toml ⇒ [tool.coverage.run] omit = */migrations/*
  • Using Environment Variables ⇒ export AVERAGE_OMIT="src/migrations/*,src/legacy_code/*"
• How To Measure And Improve Test Coverage With Poetry And Pytest
  • use Pytest-Cov
• How To Generate Beautiful & Comprehensive Pytest Code Coverage Reports (With Example)
  • coverage html

BDD (Behavior-Driven Development)

• A Complete Guide To Behavior-Driven Testing With Pytest BDD

TDD (Test-Driven Development)

• How To Practice Test-Driven Development In Python? (Deep Dive)
  • see Clean Code Notes

Hooks

• Introduction To Pytest Hooks (A Practical Guide For Beginners)
• What Is The pytest_configure Hook (A Simple Guide)

• pytest_sessionstart and pytest_sessionfinish (A Complete Guide)

Testing CLI Applications

• https://pytest-with-eric.com/pytest-advanced/pytest-argparse-typer/
  • commands as usual

Misc

• https://pytest-with-eric.com/pytest-best-practices/pytest-logging/
  • see What Is Pytest Caplog (Everything You Need To Know)
• https://pytest-with-eric.com/pytest-best-practices/pytest-read-json/
  • Define JSON in Test
  • Read An External JSON File
  • Provide JSON Data as a Fixture
  • Define JSON Using Pytest Parameters @pytest.mark.parametrize, like a parameter
  • Provide JSON At Runtime --input-json

Comparisons

• https://pytest-with-eric.com/comparisons/python-testing-frameworks/
• https://pytest-with-eric.com/comparisons/pytest-vs-unittest/#Recommendation-Unittest-vs-Pytest
  • Unittest is a good choice for simple testing scenarios, PyTest is more powerful, flexible and extensible, making it a better choice for larger, more complex testing projects.