How to install Selenium on Linux and automate your web tests



Selenium is an end to end web testing toolkit that allows you to test a web application in any browser of your choice. It does this with the help of a software called WebDriver which allows you to emulate a web browser and  test your web application in it.

In this tutorial I am going to show you how to test a simple CRUD application, by automating link clicking and form filling.

Software versions
Selenium (2.44.0)
Python 3.4.2
Linux kernel 3.13.0-37-generic and Mint 17.1 for Desktop.

Installing Selenium on Linux
To install the Selenium Bindings for Python on Linux use pip.

[leo@selenium-on-linux]$ virtualenv -p /usr/bin/python3 venv-3.4
[leo@selenium-on-linux]$ source venv-3.4/bin/activate
[leo@selenium-on-linux]$ pip3 install selenium


The webdriver for Firefox is installed along with Selenium but if you want to test your applications on chrome then you need to download the chrome driver and ensure chrome is installed on your Linux distro.

Getting started with the code.
The first thing you need to do is create an instance of the webdriver.

[leo@selenium-on-linux]$gedit selenium-tests.py
from selenium import webdriver
driver=webdriver.Chrome('/home/leo/Downloads/chromedriver')


Next you need to specify the url of the web application you need to test. I will be using a custom CMS application which is used to create, read, update and delete posts for this demonstration. Below is the screenshot of the app.

Install Selenium on Linux

driver.get("http://url-for-posts.com")
assert "Post Page Title" in driver.title


The above code will fetch the web page and check if the web page has been successfully fetched by matching the content in the page title.

Now let’s test the "Create", i.e add a post.

  link=driver.find_element_by_link_text("Add new")
NewWindow=link.click()
assert "Save" in driver.page_source


In the code above I use “find_element_by_link_text()” to perform actions on the anchor HTML element which contains the text “Add new”. You can get elements with their ID or name or even by class name. You can click on elements with the “click()” method.

On clicking the “Add new” link you get the page to create a post.

Install Selenium on Linux

Here we need to fill in the title, body, category, select whether the post will be published and then click on the "Save" button to add the post.

So let’s fill in the form with some text

#Add posts
title=driver.find_element_by_name("title")
title.send_keys("Your Title text here")
content=driver.find_element_by_name("content")
content.send_keys("Your Body text here")
category=driver.find_element_by_name("category")
category.send_keys("Your category text here")


Below is the html of the form elements.

<input type="text" name="title" required/>
<input type="text" name="content" required/>
<input type="text" name="category" required/>
<select name="published">
<option value="No">No</option>
<option value="Yes" selected="">Yes</option>
</select>
<button class="button " type="submit">Save</button>


As I mention earlier you can fetch an element by it’s name with “find_element_by_name("element name")”. You can then perform an action on it like fill it with text using “send_keys()”.

For the "select" element we will need to import the "Select" class.

from selenium.webdriver.support.ui import Select

select = Select(driver.find_element_by_name('published'))
published=select.select_by_value("Your option value")


Now we need to click on Save, however the “Save” button does not have a name attribute hence we need to use the class name.

 button=driver.find_element_by_class_name('button')
success=button.click()
assert "Add was successful" in driver.page_source

Similarly the code for update is

 #Edit Posts
link=driver.find_element_by_link_text("Edit")
newindow=link.click()
assert "Save" in driver.page_source
title=driver.find_element_by_name("title")
title.send_keys("Selenium web test edit")
content=driver.find_element_by_name("content")
content.send_keys("Selenium web test edit")
category=driver.find_element_by_name("category")
category.send_keys("Selenium web test edit")
select = Select(driver.find_element_by_name('published'))
published=select.select_by_value("0")
button=driver.find_element_by_class_name('button')
success=button.click()
assert "Update was successful" in driver.page_source


And the code for delete is

 #Delete Posts
link=driver.find_element_by_link_text("Delete")
NewWindow=link.click()
assert "Post was deleted successfully" in driver.page_source


The complete source code is available at https://github.com/Leo-g/Selenium/blob/master/python-selenium.py

I have also written a scaffolding app which will automatically creates tests for your modules along with the CRUD modules, you can download it from https://github.com/Leo-G/Flask-Scaffold and read about it at Building database driven apps in Python with Flask

You can view the code in action in the video below.

Comments and feedback is welcome.

Ref (http://selenium-python.readthedocs.org/en/latest/getting-started.html#using-selenium-to-write-tests)


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