Playwright Assertions: Getting Started Guide

The number of automation testing frameworks in the market has increased dramatically due to the constant modifications in testing methodologies. Although Selenium has been available for almost ten years, tools like Playwright and Cypress continue to advance daily.

Every tool has advantages and disadvantages, but Playwright’s execution time is faster since it uses WebSocket rather than HTTP and the WebDriver API. Everything is sent over a single connection because WebSocket is left open while the test runs.

Playwright assertions feature an internal retry mechanism and take care of test flakiness. For test assertions, it makes use of the Jest expect library. You can access several “matchers” through the expect library that checks various conditions, like toBeChecked, toBeVisible, toContainText, toBeVisible, toHaveText, etc. The default timeout for playwright assertions is 5 seconds.

This article will examine various Playwright assertion types in great detail in this Playwright tutorial.

Let’s quickly review the Playwright automation framework and examine what test assertions are.

What are Test Assertions?

In the test automation process, an assertion compares or matches the actual result with the anticipated outcome. This entails making sure the application’s status is as expected.

An assertion is a boolean expression that will be true at a particular moment in a program unless there is a programming error. An expression that contains some specified testable logic about a target under test is referred to as a test assertion.

The primary benefit of assertions is the ability to find programming errors. Among the benefits of claims are the following:

  • It is used to find small mistakes that can go undetected.
  • Errors are discovered earlier because of it.
  • Create a statement about the code’s outcomes that can be relied upon to be accurate.


How is Assertion Used in Functional Testing?

There are two ways that assertion is utilized in functional testing. Depending on their process and the way they would like the process to behave once an error has occurred, testers can utilize either hard or soft assertions.

A hard assertion will halt execution if there is a system issue that results in the assertion returning a false result. A soft assertion, on the other hand, signifies that the execution will continue and move through all subsequent steps in the chain, even if the assumption has returned a false result due to an error. Until the execution is manually restarted, no further actions will be taken.

Many strategies can be used while making an assertion. Here are several techniques.

  • An assertion may have a defined Boolean argument to determine if a stated condition is true or false. Depending on the setup, an assertion error could happen if the verification fails.

Two string parameters can be used to construct an assertion. During execution, it then determines whether the two options are equal and raises an error if they are not. This can also be executed with three string parameters, the third of which is a warning that appears in the event of an error. This is helpful for assertion testing that is more detailed and verbose.

  • Two Boolean arguments can be used to construct an assertion. During execution, it then determines whether the two factors are equal and raises an error if they are not.
  • Two Java collection objects can be used to construct an assertion. Then it determines if the same elements are in the same order in both collections. Any inconsistency or issues with the order may result in an error. Moreover, a string message is displayed when the issue can be given along with this.

Playwright: Quick Overview

An end-to-end testing tool for modern web applications like AngularJS or React.js is called Playwright. It is a Node.js library that uses a single API to automate WebKit, Firefox, and Chrome. You will be able to automate any browser that is developed on top of these browser engines. It was created by Microsoft and is free and open source. Playwright is available as a Playwright Library or as a component of the Playwright Test (this guide).

Playwright Test was developed primarily to meet the requirements of end-to-end testing. It performs all the duties of a typical test runner and then some. The playwright test enables:


  • Conduct tests on all browsers.
  • Run tests concurrently.
  • Enjoy out-of-the-box context isolation.
  • On failure, record any videos, screenshots, or other artifacts.
  • Make your POMs adaptable fixtures by integrating them.

The tool has over 48.3k Stars, 2.4k Forks, and 382 Contributors, demonstrating its popularity and rapid growth. Also, it supports every major version of Windows, Linux, and macOS. All the programming languages, including TypeScript, JavaScript, Python. .Net, and Java, are supported by your excellent infrastructure.

Along with supporting emulators and simulators, it also offers automation on actual mobile devices. You can test using Chrome or Safari browsers on an Android or iPhone/iPad.

System Prerequisites

Python 3.7 or later is needed for Playwright. The Chromium, Firefox, and WebKit browser binaries are compatible with all three operating systems (Windows, macOS, and Linux):

  • Utilizes the Windows Subsystem for Linux and Windows (WSL).
  • macOS: 10.14 or later is required.
  • Linux: You may be required to install additional requirements to launch the browsers based on your Linux distribution.

Getting Started With Playwright Assertions

You can skip forward to the section about Playwright assertions if Playwright is already installed on your device. Let’s quickly configure the Playwright framework and run the sample tests to observe how tests function before moving on to genuine Playwright assertions. Also, we’ll use it to write a functional sample of code.

Step 1: Installing Node.js on your computer. If you aren’t currently using it, you can install it on your computer by downloading it directly from the Node.js website.


Step 2: After installation, verify the version: Download and set up Visual Studio Code in step two (this will help you write formatted code, but you can pick any text editor of your choice).


Step 3: Open Visual Studio Code


Step 4: Launch your built-in terminal and issue the appropriate command.


Step 5: Open the directory


Step 6: Build a new package: default values in a JSON file.


Step 7: Install the Playwright as step seven. Playwright may be installed using npm, yarn, or the VS Code Extension.

Deep Diving into Playwright Assertions

You need different ways to assert when testing a condition, and Playwright makes this feasible much more efficiently by leveraging expect. It’s a feature that enables you to specify the status of a web page or a specific web page element.

This may entail verifying an element’s text content, the value of an input field, or the existence of a certain CSS class. This blog on locator methods has further information on it.

Let’s look at various Playwright statements now that you know what to expect.

Negative Matchers

When you want to make sure specific conditions aren’t met, you use negative matchers. It’s a form of verification that runs counter to the actual circumstance.

Web-First Assertions

Checks are repeated until a prerequisite is satisfied before moving further. Test isolation with fixtures to create a dependable testing environment and support parallelization. Test hooks build up and tear down shared resources between tests just in time.

Soft Assertions

You don’t want test execution to halt when a given condition is not met, an assertion fails when several verification steps need to be added to a page, or some are less crucial.

Soft claims are only functional while using the Playwright test runner. In a soft Playwright assertion, you merely check a condition; if it is not met, the test is marked as failing rather than interrupting the entire execution.

You can write numerous assertions in a single test using soft assertions without worrying that one of them will fail and cause the test to fail. Instead, you can verify that all statements are true if you are curious about what happens. The cycle of resolving the assertions is simplified to just one step in Playwright by utilizing soft assertions.

When Playwright uses soft assertions, the test result is checked after the test case has been entirely run. You may only sometimes wish to act differently. For instance, if the form is incomplete, and you already know it will fail, you don’t want to submit it. When you notice that the application’s status differs from what you anticipated, you may want to leave the situation early—saving time and money by going early.

Custom Expect Message

We use a custom expect message when there is a failure, and you want to display a custom error message while performing hope or verification.

Playwright Locator Assertions

The LocatorAssertions class provides locator assertions for the tests. By using expect, a new instance of LocatorAssertions is generated ().

Playwright PageAssertions

You can make Playwright claims about the page status in the tests by using PageAssertions. By calling expect, it generates a new example of PageAssertions ().

Using The Cloud Grid To Run Your Playwright Tests

With cloud-based testing solutions, you can do Playwright testing at scale across more than 50 different browser versions. Moreover, you can simultaneously execute numerous Playwright automation scripts to speed up execution times drastically.

LambdaTest is a cloud-based testing platform that allows developers to run Playwright tests by providing a cloud-based infrastructure for executing tests on more than 3000+ different browsers and operating systems combinations.

With LambdaTest, you can also run your Playwright tests on actual browsers, virtual machines, and emulators to ensure that your website or web application works as expected across different environments.


You may now have a reasonable idea of how the playwright’s assertions or expectations function. You also observed how the testing might be performed on a cloud grid. You can run tests on practically all browser and OS combinations using the cloud grid solution without worrying about how to keep them up to date. The configuration and upkeep of the tests should be something other than the tester’s concern.

Verifications, commonly referred to as assertions, are crucial when evaluating machine learning algorithms. One of the main advantages of machine learning-based testing is that tests self-heal to ensure they don’t break when the user interface of the program under test is updated.

This indicates that the test is evolving independently and dynamically. Assertions should be included throughout your test to ensure the main workflow continues operating as intended. These verification procedures act as “checkpoints” to ensure the desired behavior is displayed. For instance, you would anticipate seeing the Shopping Cart page open after selecting the “Pay Now” button so that you can confirm the payment information.