python libraries for automation testing

7 Python Libraries For Automation Testing

According to the Developer Survey, StackOverflow, Python was the fastest-growing programming language in 2020. Python is ranked 3rd in overall popularity. The support for test automation frames is one of the reasons Python is so popular. Most popular Python frameworks can be used with Selenium test automation framework and cross-browser testing.

Finding the best Selenium testing automation framework for your needs is essential. There are many Python automation test frameworks available in 2020. Many python frameworks are available, including unit test (or PyUnit), which will be the default Python testing framework for 2020.

Top 7 Python Libraries You Can Use For Automation Testing In 2023

1) PyTest

PyTest is an open-source Python web automation framework primarily used to perform unit testing. This Python testing framework is flexible and can be used to write simple automation tests or complex functional tests for libraries and applications. PyTest is simple to use. It works with Python 3.5+, PyPy 3, and Python 3.

PyTest test suites are smaller because there is a limited amount of boilerplate code and no requirement to include them in large test classes. PyTest does not have a fixed test case vocabulary, unlike the default Python testing framework 2020, which requires tests to begin with, test_ or end with _test. PyTest’s built-in features allow for automatically discovering test modules or functions.

Because of the addition of assert rewriting, which provides detailed information about failed assert statements, you don’t need to remember yourself.assert* name.

What Are The Prerequisites?

The best thing about PyTest, a Python testing framework, is its gentle learning curve. PyTest is very easy to use, especially if there are any Python testing frameworks you are familiar with.

For development, you will only need a Python IDE and a Python Package Manager to install PyTest.


The PyTest framework has many benefits. Some of the most important are listed below.

• It can be used with Python testing frameworks like unittest (or PyUnit).

• PyTest is beneficial for simple tests and can also be used to create complex functional test cases.

• Porting existing Python implementations to PyTest is easier than with other testing frameworks.

• PyTest can also be used to develop open-source projects and TDD (Test Driven Development).

• PyTest supports parameterization, which is crucial for creating test cases and suites. Parametrization allows test cases to be run with multiple input configurations, resulting in minimal code repetition.

• PyTest tests are simple to understand because there is little boilerplate code.

• It supports fixtures and classes, due to which everyday test objects are available through the lifecycle of a module/class/function/session.

• PyTest can be extended and has a rich plugin architecture. PyTest currently supports 315+ plugins.

• It supports the Parallel execution of tests through the pytestxdist plugin.

• Asserts within PyTest provide detailed details about failure scenarios.


PyTest cannot be used with any other Selenium Python testing frameworks because it has its development routines. PyTest cannot be used to port existing implementations to other Python testing frameworks without rewriting the entire code.

2) Behave

Behave is a widely-used Selenium Python test framework for Business Driven Development (BDD) testing. Behave uses Gherkin to develop scenarios and feature files. Gherkin uses simple, readable language to create test cases. This allows for Business-Driven Development.

BDD frameworks allow for better communication between team members. There is more collaboration among engineers, managers, and quality analysts. If you are familiar with other BDD frameworks like Cucumber, Cucumber, and Cucumber-JVM, it is easy to get started using Behave.

Behave is a BDD framework. It fundamentally differs from other Selenium Python testing frameworks like unittest (or PyUnit), PyTest, etc. Behave 1.2.7.dev1 is the latest version.

What Are The Prerequisites?

Behave can only be installed if you have Python above Python 2.7.14. It is helpful to have some experience with BDD tools before you can use the Behave framework.


Here are some benefits of using the Behave framework for test automation.

• Suppose the team has previous experience with any BDD framework like Cucumber or SpecFlow. In that case, it is easier to ramp up many configuration settings and environmental functions that can be used to set up fixtures, such as lighting, and other features like easy setup and cleanup.

• The PyCharm Professional Edition supports Behave.

• It can be integrated with other web frameworks like Django or Flask.

• It contains excellent tutorials and support documentation to help you start with behave Framework.

• Because tests include different scenarios, outcomes, feature files, and other elements, it is easier to add test cases.

• Non-technical people can play an essential role in developing test cases (or test scenarios) apart from technical personnel.


Here are the main cons of using the behave framework for Selenium test automation.

• The PyCharm Community Edition does not support it.

• It is challenging to share scenario steps between different feature files in Behave (*

• Parallel test execution is not supported by automated web browser testing. Parallel test execution requires additional software installation, as discussed in the threads here.

• Black-box testing can only use Behave.

• The plugin behave_parallel, which enabled parallel execution of tests with behave, is now obsolete.

3) Robot

Robot, a popular Python testing framework, is also used for Selenium automation, RPA (Robotic Process Automation), and ATDD (Acceptance Test Driven Development). It can easily be integrated with other tools, making it ideal for creating flexible automation test solutions.

The Python testing framework can be used on any operating system or application. The same implementation can be used on different platforms, including Windows, Linux, and MacOS. The robot framework’s syntax is simple because it uses human-readable keywords. Libraries that use Selenium and Python can extend the capabilities of the Robot framework. It is composed of libraries and tools that have been developed in separate projects.

What Are The Prerequisites?

Robot Framework is only available if Python version 2.7.14 and higher has been installed. The Python Package Manager (pip), the command, is used for installing the Python testing framework.


Here are some of the benefits of using Robot Framework for Selenium Test Automation:

• You don’t need programming knowledge to write test cases with the Robot framework.

• The Python testing framework can be used on any platform.

• It can be used to automate Selenium tests automation using key words ATDD and BDD.

• The Robot framework is very easy to use, as the test data syntax is easily used.

• Robot framework includes a rich library ecosystem, e.g., Appium is a mobile automation tool, and the database library allows for DB testing. Different applications can be tested.

• It comes with a great reporting system, as an HTML log is generated after each build.


Here are the main cons to using the Robot framework.

• The system does not support parallel execution of tests.
• It is difficult to create customized HTML reports.

4) PyUnit

PyUnit, also known as unittest, is the default Python test framework and is part of the Python standard libraries. The JUnit framework inspired the Python Testing Framework. It is part of the Unittest module, which has been used since Python version 2.1 was released.

Many developers want to get started with Selenium test automation like the unittest framework. Test cases are arranged in a specific nomenclature. Tests begin with test_ and end with _test.

The base class TestCase contains the assertion methods, SetUp, and TearDown routines. You can group test cases to create a TestSuite class that will allow you to build custom test runners.


These are just a few of the many benefits of the PyUnit framework.

• PyUnit, a derivative framework of the xUnit framework, has many similarities to the xUnit framework. This makes it very easy for new Python developers to get started with the unittest framework.

• Additional package installation is not required.

• You can execute the test scenarios individually or group them to create a TestSuite. Execution is easy as all you have to do to execute a test is mention their names on your terminal.

• The default output of execution is clear and easy to comprehend. The Python testing framework has many command-line options to provide more detailed output.

• The generation of test reports is speedy and takes just a few seconds.


These are the main flaws of the PyUnit framework.

• Names of test cases are still based on Java’s camelCase naming convention.
• Test implementation requires a lot of boilerplate code.
• No provision exists for color output.

5) Lettuce

Lettuce, a Python framework for BDD testing, is called Lettuce. It is based on Cucumber, which was originally designed for Ruby. Lettuce’s release names are inspired by green stuff. Lettuce 0.2.23 is the latest version and is called Kryptonite.

This Python testing framework is available as an open-source project and hosted on GitHub. As stated on their official website, lettuce was created to make testing fun and easy.


These are just a few of the benefits of the Lettuce framework.

• Lettuce, like other Python testing frameworks like Behave that support BDD, also uses the Gherkin language to create scenarios and feature files. If you are familiar with BDD testing tools, Lettuce will make it easy to start.

• Other than developers and technical personnel, there are many stakeholders in a project, such as marketing people, project managers, and others. Stakeholders, such as project managers and marketing people, can be essential in testing.

• As primary updates to feature and scenario files are required, it is simple to add test cases.


These are major flaws in the Lettuce framework.

• It’s used primarily for black-box tests.
• Lettuce allows for flawless execution. It requires communication among all stakeholders.

6) Nose2

Nose2 is a Python-based unit testing framework. It is the successor to Nose. It is built on unittest and is often referred to as an extension of unittest. Nose2 provides support for the PyUnit framework with plugins that allow test execution. This allows the automatic discovery of test cases and collects documentation.

7) Testify

In 2020, Testify will be a popular Python testing framework that can replace the unittest and the nose framework. Testify is similar to unittest, so you will not need to make any changes to the unittest tests.

Testify is a tool that can be used to automate unit, integration, and system testing. Testify 0.11.0 is the latest version. The extensible plugin system provides reporting functionality. Testify, like the Nose2 framework, also offers enhanced test discovery and class-level SetUp & TearDown method methods. This is done once for all test methods.


We have looked at some popular Python testing tools that can be used with Selenium. BDD tools like Lettuce or Behave are great for including non-technical people in test creation. The project requirements and team competency will determine the best Python testing framework. With LambdaTest, you can perform automation testing with 3000+ browsers and operating systems using these python libraries.

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