About

Welcome to "let's explore pytest", which includes several pytest examples. pytest is a testing framework that can be used to test Python code, amongst other things, and lives at www.pytest.org. Python 3 is used exclusively in this repository, though pytest can test Python 2 software.

These examples assume you are familiar with your shell or commandline, and are able to set up your environment appropriately.

Environment

You will need (the versions we are using are in parentheses):

• Python 3 (3.6.2)

• pytest (3.2.1)

• pytest-mock (1.6.0)

• pytest-xdist (1.17.1)

The conda environment file conda_environment.yml is provided, which all examples are designed to use.

Table of contents

Each example contains multiple pytest Python scripts.

1. Introductory examples

   • Introduces pytest.
   • pytest reports failing tests, and has informative output.
   • pytest searches for tests automatically.

2. Fixtures, parameterisation, and parallelisation (requires example 1)

   • Fixtures (decorated with @pytest.fixture()) are blocks of functionality that allow tests to be written in a modular way.
   • Fixtures are run when the test is run, and their output is passed to the test.
   • Fixtures can be used to parameterise tests, reducing code duplication. Each test is run individually of the others.
   • Parameterised tests run well in parallel (but be careful when testing software that itself runs in parallel!)

3. Testing software in isolation using mocking (requires example 2)