Test isolation strategies in Cypress - Build an Automation Script

Verify that each test runs independently with proper isolation

Preconditions (2)

Step 1: Open the application home page

Step 2: Verify that the counter value is 0

Step 3: Click the increment button once

Step 4: Verify that the counter value is 1

Step 5: Reload the page

Step 6: Verify that the counter value is reset to 0

Step 7: Run a second test that opens the home page

Step 8: Verify that the counter value is 0 without any clicks

✅ Expected Result: Each test runs independently without sharing state. The counter resets to 0 at the start of each test.

Automation Requirements - Cypress

Assertions Needed:

Verify counter value is 0 at test start

Verify counter increments correctly

Verify counter resets after page reload

Verify no state is shared between tests

Best Practices:

Use beforeEach hook to visit the page fresh for each test

Avoid sharing variables or state between tests

Use Cypress commands and assertions consistently

Use clear and maintainable selectors (data-cy attributes)

Automated Solution

Cypress

describe('Test isolation strategies', () => {
  beforeEach(() => {
    cy.visit('http://localhost:3000')
  })

  it('increments counter and verifies reset on reload', () => {
    cy.get('[data-cy=counter]').should('have.text', '0')
    cy.get('[data-cy=increment-btn]').click()
    cy.get('[data-cy=counter]').should('have.text', '1')
    cy.reload()
    cy.get('[data-cy=counter]').should('have.text', '0')
  })

  it('starts with counter at 0 without clicks', () => {
    cy.get('[data-cy=counter]').should('have.text', '0')
  })
})

The beforeEach hook visits the application fresh before each test to ensure no shared state.

The first test clicks the increment button and verifies the counter increments, then reloads the page and verifies the counter resets to 0.

The second test verifies the counter starts at 0 without any clicks, proving tests are isolated.

Selectors use data-cy attributes for stability and clarity.

Common Mistakes - 3 Pitfalls

Not using beforeEach to visit the page fresh

Sharing variables or DOM references between tests

Using brittle selectors like classes or ids that may change

Bonus Challenge

Now add a third test that clicks the increment button twice and verifies the counter shows 2, ensuring isolation from previous tests.

Show Hint