Mastering Pytest: A Comprehensive Unit Testing Framework

For testing professionals, the most widely used unit testing tool is definitely pytest.

pytest is a very popular and mature, fully featured Python testing framework, suitable for unit testing, UI testing, and interface testing. It is similar to the unit testing framework unittest, but pytest is more concise and efficient.

Many testers feel that pytest is the best framework for testing after learning unittest and pytest, because pytest has many advantages:

Simple and flexible, easy to get started.
Supports parameterization.
Can mark tests with features and attributes.
pytest has many third-party plugins and can be customized for extensions, such as pytest-selenium (integrates Selenium), pytest-html (generates HTML test reports), pytest-rerunfailures (re-executes failed cases), etc.
Using skip and xfail can handle unsuccessful test cases.
Can distribute tests across multiple CPUs using the xdist plugin.
Allows using assert directly for assertions, without needing to use self.assert *.
Convenient for use in continuous integration tools.

Installing Pytest

Open the Xfce terminal, enter the command sudo pip install pytest and press enter, as shown in the screenshot below:

After installation, enter the command pytest -V or pytest --version to check if pytest is installed successfully, as shown in the screenshot below:

If the version information such as pytest version appears, it indicates that the installation was successful.

Practical Experience

We create a new folder test under /home/shiyanlou/, then use VS Code to open the test folder. Next, create a new py file in the test folder and name it test_example.py. The content of test_example.py is as follows:

import pytest
def add(a, b):
    return a + b
def test_add1():
    print("The result of add(2, 3) is: {}".format(add(2, 3)))    
    assert add(2, 3) == 5
def test_add2():
    assert add(2, 3) == 6
if __name__ == "__main__":
    pytest.main()

There are two ways to run the tests marked by pytest: adding pytest.main() in the py file and using the run button in the upper right corner of VS Code, or running the command in the command line. In this experiment, we will run it in the command line.

Open the terminal in VS Code, enter the command cd /home/shiyanlou/test/ to enter the test folder, then type pytest and press enter, as shown in the screenshot below:

From the running results, we can see some information:

It shows the platform on which it is running, the Python version, and the execution root directory.
The collected test cases, collected 2 items indicates that a total of two test cases were detected.
The executed test files and the results of the test cases in the test files, where . indicates a passed test case, and F indicates a failed test case.
[100%] indicates the overall progress of running all test cases.
If a test case fails, it will display the specific test case and highlight where the error occurred.
At the end, it will give a simple statistic of the overall situation, for example, 1 failed, 1 passed in 0.09s.

Systematic Learning

SQOOP has launched“Practical Project of Pytest Automation Framework,”which will guide you through a systematic learning of Pytest through 11 courses, gradually mastering the Pytest framework, PyMySQL, logging, and OpenPYXL, as well as data-driven models and keyword-driven models in automation testing.

Pytest is a very popular and beloved testing framework. It is characterized by being simple, flexible, easy to get started, powerful, rich in plugins, and supports parameterization, making it a powerful tool in automated testing. The course will comprehensively introduce the operations of the Pytest framework and will use data-driven models and keyword-driven models.