What is UnsupportedCommandException in Selenium?

Hari Mahesh

Exceptions in Selenium are types of errors that occur during the test execution. These exceptions are thrown when Selenium WebDriver faces an issue not handled in the automation script. There could be various reasons for these exceptions to be raised. These exceptions help the testers understand why the test script failed and work on the necessary actions.

One such exception is UnsupportedCommandException. So, let’s get into more detail about this exception, the root causes, and how we can resolve it.

UnsupportedCommandException – Root Cause

This exception occurs when we try to execute a command that the browser or Selenium WebDriver does not support. However, this is not a frequent exception which is thrown. But there can be scenarios when the browser does not use some commands or when there is a version mismatch between WebDriver and the browser.

There can be many reasons for throwing this error. Let’s review each.

• Browser Compatibility Issues: It’s not mandatory that all browsers support every Selenium command. For example, a command that works flawlessly in Google Chrome may not be available or function properly in Safari. The root cause for this issue is the difference in the underlying browser engines. Blink is the browser engine for Chrome, and Gecko is for Firefox. Also, if you specify some settings specific to Google Chrome, it will not work in other browsers. In those scenarios, UnsupportedCommandException can be thrown.

• WebDriver Limitations: Every WebDriver has its limitations. For example, a ChromeDriver may support certain functionalities that may not be available in GeckoDriver. When the test script tries to execute the command not supported by the driver, it can raise UnsupportedCommandException.

• Incorrect Command Usage: Sometimes, the issue happens when we misuse the command. For example, the exception will be thrown if we use the select command on a regular button or link. This occurs mainly because of the misunderstanding about the UI element to be automated.

• Using Deprecated or Removed Commands: If the automation scripts were created using older commands, and the newer version doesn’t support those commands. It means those commands got deprecated with more recent versions of Selenium WebDriver. Then, while executing these commands, this exception will be thrown.

• Driver-Server Version Mismatch: A mismatch between Selenium WebDriver and the browser driver version may lead to compatibility issues. Some commands might have been introduced or deprecated between versions. For instance, if you update your Selenium WebDriver but not your ChromeDriver, specific new commands or enhancements in the WebDriver might not be recognized by the older version of the ChromeDriver, causing an UnsupportedCommandException.

Resolving UnsupportedCommandException

Use the below resolutions to avoid the UnsupportedCommandException in your Selenium scripts:

• Update WebDriver and Browser: Ensure your browser and its corresponding WebDriver are updated to the latest versions. This can resolve issues where a command is not supported due to outdated software. For instance, if using Chrome, you would update the Chrome browser and the ChromeDriver to their latest versions.

  # Example: Update ChromeDriver using webdriver-manager in Python
  from webdriver_manager.chrome import ChromeDriverManager
  from selenium import webdriver
  driver = webdriver.Chrome(ChromeDriverManager().install())

• Switch to a Supported Browser or WebDriver: If a command is not supported in your current browser or WebDriver, switch to one that supports it. For example, if a command isn’t supported in Internet Explorer, try using Chrome or Firefox instead.

  # Example: Switching to Firefox if Chrome is not supported
  from selenium import webdriver
  driver = webdriver.Firefox(executable_path='path_to_geckodriver')

• Use Correct Syntax and Command: Make sure you are using the correct syntax and the appropriate command for the operation you are trying to perform. Consult the Selenium documentation for the correct usage of commands.

  # Example: Correctly using the find_element method
  from selenium import webdriver
  driver = webdriver.Chrome()
  driver.get("http://example.com")
  element = driver.find_element("id", "element_id")

• Handle Browser-Specific Functionalities: For browser-specific functionalities, use conditional logic in your script to handle different browsers differently. This avoids using commands that are unsupported in a particular browser.

  # Example: Using conditional logic for browser-specific commands
  from selenium import webdriver
  driver = webdriver.Chrome()
  
  if driver.name == "chrome":
    # Perform Chrome-specific operation
  elif driver.name == "firefox":
    # Perform Firefox-specific operation

• Avoid Using Deprecated Commands: Replace deprecated commands with their newer alternatives per the latest Selenium documentation. This is crucial when dealing with newer versions of Selenium.

  # Example: Replacing a deprecated command with a new one
  from selenium.webdriver.common.by import By
  # Replacing deprecated find_element_by_* method
  element = driver.find_element(By.ID, "element_id")

How testRigor is the Game-Changer?

Selenium was once the most preferred automation tool by organizations. However, as the technology advanced and the market demand increased, Selenium could not keep up with the fast pace of software development. Selenium is most preferred for the waterfall method. However, as testing activities have moved to a shift-left approach, Selenium couldn’t be a good choice for E2E testing. Here are the disadvantages of using Selenium.

With agile and extreme programming taking a significant role in SDLC, a more competent automation tool is needed. testRigor meets all the requirements for the modern SDLC. It is packed with many features that tremendously ease the testing team’s effort.

Let’s look at a few top features of testRigor that stand out.

• Generative AI: testRigor, with its generative AI, helps in test case generation, where generative AI algorithms can generate test cases by analyzing the test description you provided. Also, generative AI helps create test data required for test cases.
• No Code Dependency: testRigor helps write test scripts in plain English, which means there is no need to be proficient in any programming language. Just write the test script in English, and testRigor puts it into action with its AI algorithms.
• Easy Integrations: testRigor provides built-in integrations with test management tools, bug management tools, CI providers, infrastructure providers, etc., to ease your task to a great extent.
• Testing PowerHouse: testRigor supports different types of testing like web and mobile browser testing, mobile app testing, desktop testing, API testing, visual testing, and accessibility testing.

EndNotes

The current market trend is to have more frequent releases to give customers a flawless and smooth experience. To make that happen quickly, testing plays a crucial role. The automation tool must be intelligent enough to expand the automation coverage easily. You can choose testRigor as it can play a vital role in achieving this successfully. With its support, not just QA but also developers, business analysts, the management team, and other stakeholders can ensure the quality of the application. This, in turn, saves cost, effort, and time and guarantees impeccable product quality.

“We spent so much time on maintenance when using Selenium, and we spend nearly zero time with maintenance using testRigor.”

Keith Powe VP Of Engineering - IDT