How to clear browser cache within a Cypress test

When using Cypress for automated testing, ensuring a clean browser environment without cache during each test run is essential. This guarantees consistent and reproducible test results. The following are several methods to clear browser cache in Cypress tests:

1. Creating Custom Commands with Cypress.Commands

To clear the browser cache and cookies, add custom commands in the commands.js file. For example:

javascript
Cypress.Commands.add('clearCache', () => {
  indexedDB.deleteDatabase('yourDatabase');
  cy.clearCookies();
  cy.clearLocalStorage();
});

Then, in your test files, call this command using cy.clearCache().

2. Automatically Clearing Before Each Test

In the cypress/support/index.js file, use the beforeEach hook to automatically clear cache and cookies before each test:

javascript
beforeEach(() => {
  cy.clearCookies();
  cy.clearLocalStorage();
});

This ensures that each test case starts with a consistent environment.

3. Using Cypress Configuration

Cypress also supports setting certain behaviors in the cypress.json configuration file, such as:

json
{
  "clearCookiesBeforeEveryTestRun": true
}

Although this is not a valid Cypress configuration option (as it's only an example), it illustrates how configuration can control certain behaviors.

4. Using Plugins or External Tools

In some cases, plugins or external tools may be required to manage browser cache. For example, using browser extensions to clear cache before each test. This approach is more complex and typically reserved for very specific requirements.

Example: Actual Test Case

javascript
describe('Login Test', () => {
  beforeEach(() => {
    cy.clearCache();  // Using custom command to clear cache
  });

  it('should display the login form', () => {
    cy.visit('/login');
    cy.get('form').should('be.visible');
  });

  it('should allow user to submit login form', () => {
    cy.visit('/login');
    cy.get('input[name="username"]').type('user1');
    cy.get('input[name="password"]').type('password1');
    cy.get('form').submit();
    cy.url().should('include', '/dashboard');
  });
});

By using these methods, you can effectively manage and clear browser cache in Cypress tests, ensuring a clean execution environment for each test, thereby improving the accuracy and reliability of your tests.