Notes

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Selenium ​

A tried and true tool for creating end-to-end (e2e) tests.

Useful for automated testing and data retrieval.

Installation ​

Get the WebDriver installed for the browser(s) you want to test with.

IMPORTANT: If using the snap based version of chromium on linux, the chromedriver is included there. It's important to use that version, otherwise the chromedriver will have trouble accessing the isolated instance of the browser.

In snap, the chrome driver is available /snap/bin/chromium.chromedriver

https://stackoverflow.com/a/61980562

Some of the steps I found necessary to get this working

vi ~/.profile 

PATH="/snap/bin:$PATH"

source ~/.profile
vi ~/.profile 

PATH="/snap/bin:$PATH"

source ~/.profile

Chrome Driver ​

If not using the snap version of Chrome, you may need to download the chrome driver separately

https://chromedriver.chromium.org/getting-started

Check your version of Chrome (Menu -> About Chromium). Download the right version of the driver.

https://chromedriver.chromium.org/downloads

Extract the driver

Help WebDriver find the downloaded ChromeDriver executable Any of these steps should do the trick:

    include the ChromeDriver location in your PATH environment variable

env
mv ~/Downloads/chromedriver /usr/local/bin/
sudo chown account: /usr/local/bin/chromedriver
env
mv ~/Downloads/chromedriver /usr/local/bin/
sudo chown account: /usr/local/bin/chromedriver

Language Bindings ​

The selenium-webdriver has bindings for many languages.

Python ​

pip install selenium
pip install selenium

via

https://selenium-python.readthedocs.io/installation.html#installing-python-bindings-for-selenium

  1. Installation — Selenium Python Bindings 2 documentation

https://selenium-python.readthedocs.io/
Selenium with Python — Selenium Python Bindings 2 documentation

Try out the getting started script:

python
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By

driver = webdriver.Firefox()
driver.get("http://www.python.org")
assert "Python" in driver.title
elem = driver.find_element(By.NAME, "q")
elem.clear()
elem.send_keys("pycon")
elem.send_keys(Keys.RETURN)
assert "No results found." not in driver.page_source
driver.close()
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By

driver = webdriver.Firefox()
driver.get("http://www.python.org")
assert "Python" in driver.title
elem = driver.find_element(By.NAME, "q")
elem.clear()
elem.send_keys("pycon")
elem.send_keys(Keys.RETURN)
assert "No results found." not in driver.page_source
driver.close()

https://selenium-python.readthedocs.io/getting-started.html
2. Getting Started — Selenium Python Bindings 2 documentation

Then run it

python get_data.py
python get_data.py

If all goes well, a browser should pop up, go to the python.org site, and then close.

If you want to interact with the browser before it closes, comment out driver.close() in the script and then run python interactively

python -i get_data.py
python -i get_data.py

This is a good point to update the script to go to any login page so you can do that step manually. Automating logins is often difficult and opens up the risk of exposing credentials.

From here create a helpers.py script that you can import and subsequently reload your module without needing to restart your active browser context (and consequently, re-login).

Note: this approach is more useful for data retrieval than it is for testing. Tests should not have side effects

For python3, the import module functionality has moved

import importlib
importlib.reload(module)
import importlib
importlib.reload(module)

An example starter helper.py could look something like:

from selenium.webdriver.common.by import By

def get_list(driver):
  driver.get("https://python.org")
from selenium.webdriver.common.by import By

def get_list(driver):
  driver.get("https://python.org")

Locating content ​

The By wrapper helps

from selenium.webdriver.common.by import By
from selenium.webdriver.common.by import By

Use the browser markup inspector to find the right way to select the element.

https://selenium-python.readthedocs.io/locating-elements.html

From here, refine the child elements that you want, or work with the related markup directly

element.get_attribute('innerHTML')
element.get_attribute('innerHTML')

Node Javascript ​

https://www.npmjs.com/package/selenium-webdriver

cd ~/projects
mkdir selenium-shared
cd selenium-shared

yarn init
yarn add --dev selenium-webdriver
cd ~/projects
mkdir selenium-shared
cd selenium-shared

yarn init
yarn add --dev selenium-webdriver

Now the tests can live locally or in your project directory.

Create a test script (e.g. init.js) and add the following to try it out

const {Builder, By, Key, until} = require('selenium-webdriver');

(async function example() {
  let driver = await new Builder().forBrowser('chrome').build();
  try {
    await driver.get('http://www.google.com/ncr');
    await driver.findElement(By.name('q')).sendKeys('webdriver', Key.RETURN);
    await driver.wait(until.titleIs('webdriver - Google Search'), 1000);
  } finally {
    await driver.quit();
  }
})();
const {Builder, By, Key, until} = require('selenium-webdriver');

(async function example() {
  let driver = await new Builder().forBrowser('chrome').build();
  try {
    await driver.get('http://www.google.com/ncr');
    await driver.findElement(By.name('q')).sendKeys('webdriver', Key.RETURN);
    await driver.wait(until.titleIs('webdriver - Google Search'), 1000);
  } finally {
    await driver.quit();
  }
})();

then run with

node init.js
node init.js

Local Testing ​

Some settings may be necessary to handle "Connection Is Not Private"

http://blogs.stevelongchen.com/2020/05/14/selenium-how-to-disable-or-bypass-connection-is-not-private-for-chrome-and-firefox/

UI Testing ​

One benefit over Cypress is that Selenium works when testing remote services. One downside when compared with Cypress is that Selenium does not offer tight integration with the node application.

It may be possible to get some of the nice testing integration by using Selenium with Mocha and Chai.

https://nehalist.io/selenium-tests-with-mocha-and-chai-in-javascript/