Selenium Python Tutorial: Getting Started With Pytest

Advantages Of Pytest Framework

Here are some of the primary advantages of Selenium testing with Python and pytest:

• It can be used for simple as well as complex functional test cases for applications and libraries. You can even use a pytest to execute multiple test cases.

• Existing Python code that uses other Python testing frameworks can be ported easily to the pytest.

• The Selenium test automation framework can be used for projects that practice TDD (Test Driven Development) as well as open-source projects.

• Switching to the pytest framework is easy as it is compatible with other Python test frameworks such as PyUnit (or unit test) and Nose2.

• Parameterization is supported in the pytest which helps in the execution of the same test with different configurations using a simple marker.

• The availability of pytest fixtures makes it easy for common test objects to be available throughout a module/class/session/function.

Getting Started With Selenium Testing With Python and Pytest

As the pytest is not a part of the standard Python library, it needs to be installed separately. To install pytest, you have to execute the following command on the terminal (or command prompt) that makes use of the Python package manager (pip):

pip install –U pytest

The following command should be executed to verify the status of the installation:

pytest --version

Here is the output when the installation is performed on the Windows 10 machine:

PyCharm is the most popular IDE for development using the Python language.

Depending on the requirement, you can opt for the Community version or the Professional version. The community version of PyCharm is free and open-source; the same can be downloaded from PyCharm official download link.

Once the PyCharm installation is complete, it is necessary to set the default test runner as a pytest. Navigate to File, Settings, Tools, Python Integrated Tools, and select a pytest to make it the default test runner.

As the pytest will be used for automated browser testing, we also have to install the Selenium package for Python. Selenium for Python can be installed by executing the following command on the Windows terminal (or prompt) or the terminal of PyCharm.

pip install -U selenium

Prerequisites For Selenium Testing With Python and Pytest

For using the pytest framework, Python needs to be installed on the machine. Python for Windows can be downloaded from here. Along with Python 3.5+, the pytest is also compatible with PyPy3. Prior knowledge of Python will help get started with Selenium automation testing with pytest.

Since the pytest will be used for automated browser testing, Selenium WebDriver for the browser under test needs to be installed. Download links for Selenium WebDriver for popular browsers are below:

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File naming nomenclature — File name should be test_*.py or *_test.py

Test Method nomenclature — Test method should be of the format test*

These are mandatory requirements as the pytest has features built-in to the framework that supports the auto-discovery of test modules and test methods (or functions).

Running Your First Selenium Test Automation Script With Python and Pytest

To demonstrate Selenium testing with Python and pytest, I’ll  test the LambdaTest ToDo App scenario for this Selenium Python tutorial:

1. Navigate to the URL https://lambdatest.github.io/sample-todo-app/

2. Select the first two checkboxes

3. Send ‘Happy Testing at LambdaTest’ to the textbox with id = sampletodotext

4. Click the Add Button and verify whether the text has been added or not

The implementation file (Sample.py) can be located in any directory as the invocation will be done using the filename.

 Implementation

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#Implementation of Selenium test automation for this Selenium Python Tutorial

import pytest

from selenium import webdriver

import sys

from selenium.webdriver.chrome.options import Options

from selenium.webdriver.common.keys import Keys

from time import sleep

def test_lambdatest_todo_app():

    chrome_driver = webdriver.Chrome()

    chrome_driver.get('https://lambdatest.github.io/sample-todo-app/')

    chrome_driver.maximize_window()

    chrome_driver.find_element_by_name("li1").click()

    chrome_driver.find_element_by_name("li2").click()

    title = "Sample page — lambdatest.com"

    assert title == chrome_driver.title

    sample_text = "Happy Testing at LambdaTest"

    email_text_field = chrome_driver.find_element_by_id("sampletodotext")

    email_text_field.send_keys(sample_text)

    sleep(5)

    chrome_driver.find_element_by_id("addbutton").click()

    sleep(5)

    output_str = chrome_driver.find_element_by_name("li6").text

    sys.stderr.write(output_str)

    sleep(2)

    chrome_driver.close()

Code Walk-Through

Step 1 — The necessary modules are imported, namely pytest, sys, selenium, time, etc.

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#importing necessary module for Selenium Python tutorial

import pytest

from selenium import webdriver

import sys

Step 2 — The test name starts with test_ (i.e. test_lambdatest_todo_app) so that the pytest can identify the test. Using the Selenium WebDriver command, the Chrome WebDriver is instantiated. The URL is passed using the .get method in Selenium.

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#Initiating ChromeDriver for this Selenium Python Tutorial

def test_lambdatest_todo_app():

chrome_driver = webdriver.Chrome()

chrome_driver.get('https://lambdatest.github.io/sample-todo-app/')

chrome_driver.maximize_window()

Step 3 — The Inspect Tool feature of the Chrome browser is used to get the details of the required web elements i.e. checkboxes with name li1and li2 and button element with id = addbutton.

Once the web elements are located using the appropriate Selenium methods [i.e. find_element_by_name(), find_element_by_id()], necessary operations [i.e. click(), etc.] are performed on those elements.

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#Identifying Required Elements and performing necessary operation on them for Selenium Python tutorial

chrome_driver.find_element_by_name("li1").click()

chrome_driver.find_element_by_name("li2").click()

.........................

.........................

chrome_driver.find_element_by_id("addbutton").click()

sleep(5)

output_str = chrome_driver.find_element_by_name("li6").text

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Step 4 — The close() method of Selenium is used to release the resources held by the WebDriver instance.

chrome_driver.close()

Execution

The following command is executed on the terminal after navigating to the directory that contains the test code.

pytest SampleTest.py --verbose --capture=no

Using --verbose, the verbosity level is set to default. The --capture=no is used to capture only stderr and not stdout.

For adding more options to the pytest command, you can execute the --help option with pytest.

pytest --help

Here is the snapshot with the test execution in progress:

Wrapping It Up

In this introductory article of the ongoing Selenium Python tutorial series, I gave you a  brief look at Selenium testing with Python and pytest. pytest is one of the most popular Selenium test automation frameworks in Python. 

We also demonstrated the usage of the pytest framework with Selenium where the URL under test was the LambdaTest ToDo App. pytest framework mandates a particular naming nomenclature for test methods and tests files as it has auto-discovery of test modules and test methods.

The availability of fixtures and classes makes it an ideal framework for automation testing, including cross-browser testing.

You should now be able to do Selenium Python testing with pytest.In case of any doubt, do reach out to us. Feel free to share this article with your peers and help us reach out to them. That’s all for now.

Happy Testing!