Cypress Clear Session Storage

Introduction to Clearing Session Storage in Cypress

Session storage is a widely used storage mechanism for web applications. It stores data in key-value pairs in a user’s browser for the duration of the user’s session. Cypress, a JavaScript-based end-to-end testing tool, also supports session storage.
Using Cypress, we can easily manipulate and test the behavior of session storage in our web applications.
However, sometimes we may need to clear the session storage during testing to ensure that our tests run correctly. This is where the cy.sessionStorage() command comes into play.

The cy.sessionStorage() command allows us to interact with the session storage of the browser under test. By using the clear() method, we can easily clear the session storage during our tests.

Cypress also provides us with the ability to clear the session storage automatically before each test using the beforeEach() method. This ensures that each test starts with a clean slate and reduces the likelihood of any interference between tests.

Why Clearing Session Storage is Important for Cypress Testing

When it comes to Cypress testing, clearing session storage can be an essential step in ensuring accurate and reliable test results. Session storage is a browser feature that allows websites to store information locally on a user’s device. This feature is often used to store important user data such as login credentials, user preferences or shopping cart contents.

However, the presence of session storage can interfere with automated tests that are designed to work with a clean slate for each test run. If session storage is not properly cleared before each test, the stored data can impact test results and cause false positives or negatives. Additionally, if a test accidentally updates the session storage data, it can impact subsequent test results and make it difficult to debug the issue.

Furthermore, clearing session storage helps ensure that your tests will be effective across different testing environments. For instance, if session storage data is not cleared, it can create false positives or negatives in one testing environment, but not in another, leading to inconsistent and unreliable test results.

In conclusion, clearing session storage before each test run is an important step in ensuring accurate and reliable Cypress test results. It’s a small but crucial step in creating trust in the testing process and ultimately in the overall quality of your website or web application.

How to Clear Session Storage in Cypress: A Step-by-Step Guide

In Cypress, session storage is used to store data that needs to be accessed within a user’s session. However, sometimes there may be a need to clear the session storage to start fresh or to simulate a new user session. Here’s a step-by-step guide on how to clear session storage in Cypress:

  1. Use the Cypress.Commands.add() method to create a new custom command.
  2. Inside the custom command, use the Cypress.Commands.overwrite() method to overwrite the default window.sessionStorage.clear() method with the cy.window().then((win) => {win.sessionStorage.clear()}) command.
  3. Now you can call the custom command in your tests by using the custom command name (e.g. cy.clearSessionStorage()).
  4. Once the custom command is executed, the session storage will be cleared and ready for your next test.

Overall, the process of clearing session storage in Cypress is simple and straightforward. By following this guide, you can easily incorporate this step into your Cypress test suite and ensure that your tests are running smoothly.

Best Practices for Clearing Session Storage in Cypress

When writing tests with Cypress, clearing session storage can be important to ensure that each test starts with a clean state. Here are some best practices to follow when clearing session storage in Cypress:

  • Clear session storage before each test: It’s important to clear session storage before each test to ensure that there is no data left over from previous tests.
  • Use the Cypress ‘clear’ command: In Cypress, you can use the ‘clear’ command to clear session storage. This command clears all keys and values in session storage.
  • Clear local storage as well: Depending on your application, it may also be necessary to clear local storage in addition to session storage.
  • Consider using a plugin: If you find yourself needing to clear session and/or local storage frequently, consider using a Cypress plugin to simplify the process.

By following these best practices, you can ensure that your Cypress tests are running with the cleanest state possible, leading to more reliable and accurate test results.

Troubleshooting: Common Errors When Clearing Session Storage in Cypress

Clearing session storage is an important aspect of Cypress testing as it can help ensure that each test is executed with a fresh state, preventing any potential errors caused by cached information. However, there are some common errors that might occur while clearing session storage in Cypress, and here are some possible troubleshooting steps.

Error 1: “cy.clearSessionStorage() failed because this command should be chained off of a previous command”

This error might occur if the cy.clearSessionStorage() command is used without chaining it off a previous command. To solve this issue, the command should be chained to a previously executed command, for example:


Error 2: “cy.clearSessionStorage() failed because the localStorage property does not exist on ‘null'”

This error may occur if the cy.clearSessionStorage() command is used before visiting a page, or if the page does not have any local storage. To fix this issue, ensure that the page has local storage, or visit the page before attempting to clear the session storage:


Error 3: “Uncaught DOMException: Failed to execute ‘setItem’ on ‘Storage’: Setting the value of ‘key’ exceeded the quota.”

This error might occur when the session storage exceeds its limit. To solve this issue, you can either decrease the amount of data stored in the session storage or augment the maximum amount of the session storage.

By keeping these troubleshooting tips in mind, you can resolve some of the most common errors that might occur when clearing session storage in Cypress and ensure that your tests are running smoothly.

Advanced Techniques for Clearing Session Storage in Cypress

Clearing session storage is an important aspect of UI testing with Cypress, as it ensures that each test starts with a fresh state. While Cypress provides a simple cy.clearSessionStorage() command to clear the entire session storage, there are advanced techniques that can be used to clear specific items or subsets of data.

Clearing Specific Items in Session Storage

To clear specific items in session storage, you can use the window.sessionStorage.removeItem() method. This method takes a key parameter, which is the name of the item you wish to remove. Here is an example:

it('clears specific item in session storage', () => {
  // set item in session storage
  window.sessionStorage.setItem('myItem', 'some value');

  // verify item is set
  expect(window.sessionStorage.getItem('myItem')).to.equal('some value');

  // clear specific item

  // verify item is removed

Clearing Subsets of Data in Session Storage

If you have a large amount of data stored in session storage and only want to clear a subset of it, you can use the Object.keys() method to get an array of all keys in session storage. You can then filter this array to remove keys that do not match a specific pattern, like a prefix. Here is an example filtering all keys with a prefix of ‘myPrefix’:

it('clears data with specific prefix in session storage', () => {
  // set items in session storage
  window.sessionStorage.setItem('myPrefix_key1', 'some value');
  window.sessionStorage.setItem('myPrefix_key2', 'some other value');
  window.sessionStorage.setItem('anotherPrefix_key', 'ignore me');

  // verify items are set
  expect(window.sessionStorage.getItem('myPrefix_key1')).to.equal('some value');
  expect(window.sessionStorage.getItem('myPrefix_key2')).to.equal('some other value');
  expect(window.sessionStorage.getItem('anotherPrefix_key')).to.equal('ignore me');

  // clear items with specific prefix
  const keys = Object.keys(window.sessionStorage);
    .filter(key => key.startsWith('myPrefix_'))
    .forEach(key => window.sessionStorage.removeItem(key));

  // verify items are removed
  expect(window.sessionStorage.getItem('anotherPrefix_key')).to.equal('ignore me');

By using these advanced techniques, you can have more control over managing session storage in your Cypress tests and have them run more efficiently.

Conclusion: The Benefits of Clearing Session Storage in Cypress Testing

In conclusion, clearing session storage during Cypress testing can provide a number of benefits. For one, it ensures that tests are starting with a clean slate every time, preventing any potential issues that may arise from previously stored session data. It also helps to make tests more reliable and easier to troubleshoot, as you know exactly what data is being used in each test run.

Overall, incorporating the clearing of session storage into your Cypress testing process is a simple but effective way to improve the efficiency and accuracy of your tests.

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