data-cy attributes for test stability in Cypress - Build an Automation Script

Verify login functionality using data-cy attributes

Preconditions (4)

Step 1: Enter '[e-mail]' in the email input field identified by data-cy='email-input'

Step 2: Enter 'Password123!' in the password input field identified by data-cy='password-input'

Step 3: Click the login button identified by data-cy='login-button'

Step 4: Wait for the page to navigate to the dashboard

✅ Expected Result: User is redirected to the dashboard page with URL containing '/dashboard'

Automation Requirements - Cypress

Assertions Needed:

Verify the URL contains '/dashboard' after login

Verify the login button is clickable

Verify input fields accept text

Best Practices:

Use data-cy attributes for element selectors to improve test stability

Avoid using CSS classes or IDs that may change frequently

Use Cypress commands like cy.get('[data-cy="..."]') for selectors

Use explicit assertions to confirm actions succeeded

Automated Solution

Cypress

describe('Login Test Using data-cy Attributes', () => {
  beforeEach(() => {
    cy.visit('/login');
  });

  it('should login successfully using data-cy selectors', () => {
    cy.get('[data-cy="email-input"]').type('[e-mail]');
    cy.get('[data-cy="password-input"]').type('Password123!');
    cy.get('[data-cy="login-button"]').should('be.visible').and('be.enabled').click();
    cy.url().should('include', '/dashboard');
  });
});

This Cypress test visits the login page before each test to ensure a fresh start.

It uses cy.get('[data-cy="..."]') to select elements by their data-cy attributes, which are stable and unlikely to change, making tests more reliable.

The test types the email and password into the respective inputs, then checks that the login button is visible and enabled before clicking it.

Finally, it asserts that the URL includes '/dashboard' to confirm successful login.

Common Mistakes - 3 Pitfalls

Using CSS classes or IDs for selectors instead of data-cy attributes

{'mistake': 'Not waiting for elements to be visible or enabled before interacting', 'why_bad': 'Interacting with elements too early can cause flaky tests or errors.', 'correct_approach': "Use Cypress assertions like .should('be.visible') and .should('be.enabled') before clicking or typing."}

{'mistake': 'Hardcoding selectors without attribute quotes or incorrect syntax', 'why_bad': 'Incorrect selector syntax causes tests to fail to find elements.', 'correct_approach': 'Always use correct CSS attribute selector syntax, e.g., cy.get(\'[data-cy="email-input"]\')'}

Bonus Challenge

Now add data-driven testing with 3 different sets of login credentials using data-cy selectors

Show Hint

Practice

1. Why are data-cy attributes recommended for locating elements in Cypress tests?

easy

A. They improve page loading speed.

B. They automatically generate test data for forms.

C. They provide stable and unique selectors that don't change with UI updates.

D. They style elements with CSS.

Solution

1. Step 1: Understand the purpose of data-cy attributes

   data-cy attributes are used as custom selectors in tests to find elements reliably.

2. Step 2: Recognize why stability matters in tests

   Using data-cy keeps tests stable because these attributes don't change when the page design or CSS changes.

3. Final Answer:

   They provide stable and unique selectors that don't change with UI updates. -> Option C

4. Quick Check:

   Stable selectors = They provide stable and unique selectors that don't change with UI updates. [OK]

Hint: Remember: stable selectors = stable tests [OK]

Common Mistakes:

• Thinking data-cy affects page style
• Confusing data-cy with test data generation
• Assuming data-cy improves performance

2. Which of the following is the correct way to select an element with data-cy='submit-button' in Cypress?

easy

A. cy.get('[data-cy=submit-button]')

B. cy.get('submit-button')

C. cy.get('#submit-button')

D. cy.get('.submit-button')

Solution

1. Step 1: Recall the syntax for attribute selectors in Cypress

   To select an element by attribute, use cy.get('[attribute=value]').

2. Step 2: Match the attribute and value correctly

   The attribute is data-cy and value is submit-button, so the selector is [data-cy=submit-button].

3. Final Answer:

   cy.get('[data-cy=submit-button]') -> Option A

4. Quick Check:

   Attribute selector syntax = cy.get('[data-cy=submit-button]') [OK]

Hint: Use square brackets for attribute selectors [OK]

Common Mistakes:

• Omitting square brackets in selector
• Using ID or class selectors instead of attribute
• Not quoting attribute values when needed

3. Given this HTML snippet:

<button data-cy="login-btn">Login</button>

What will the following Cypress command do?

cy.get('[data-cy=login-btn]').click()

medium

A. Find the button with data-cy 'login-btn' and click it.

B. Throw an error because the selector is invalid.

C. Click the first button on the page regardless of attributes.

D. Find all buttons and click them all.

Solution

1. Step 1: Understand the selector usage

   The command cy.get('[data-cy=login-btn]') selects the element with attribute data-cy equal to login-btn.

2. Step 2: Understand the action performed

   The .click() method clicks on the selected element, which is the login button.

3. Final Answer:

   Find the button with data-cy 'login-btn' and click it. -> Option A

4. Quick Check:

   Selector + click = Find the button with data-cy 'login-btn' and click it. [OK]

Hint: Selector matches attribute, then perform action [OK]

Common Mistakes:

• Assuming selector is invalid syntax
• Thinking it clicks all buttons
• Confusing attribute selector with tag selector

4. You wrote this Cypress test:

cy.get('[data-cy=submit]').click()

But the test fails with "Cannot find element" error. What is the most likely cause?

medium

A. The click() method is not supported on buttons.

B. The element does not have a data-cy='submit' attribute.

C. The selector syntax is incorrect; it should be cy.get('data-cy=submit').

D. Cypress cannot click elements inside forms.

Solution

1. Step 1: Check the selector correctness

   The selector [data-cy=submit] is correct syntax for attribute selection.

2. Step 2: Identify why element is not found

   If the test fails to find the element, it likely means the element does not have the data-cy='submit' attribute in the HTML.

3. Final Answer:

   The element does not have a data-cy='submit' attribute. -> Option B

4. Quick Check:

   Missing attribute = The element does not have a data-cy='submit' attribute. [OK]

Hint: Check if attribute exists on element first [OK]

Common Mistakes:

• Blaming click() method for failure
• Using wrong selector syntax
• Assuming Cypress can't click form elements

5. You want to make your Cypress tests more stable by adding data-cy attributes. Which practice will best improve test stability?

hard

A. Use data-cy attributes only on buttons, ignoring other elements.

B. Add data-cy attributes with random values generated at runtime.

C. Use CSS classes as selectors instead of data-cy attributes for flexibility.

D. Add unique, descriptive data-cy attributes to key elements and use them in tests.

Solution

1. Step 1: Understand the goal of data-cy attributes

   They help tests find elements reliably and keep tests stable even if UI changes.

2. Step 2: Identify best practice for stability

   Using unique, descriptive data-cy attributes on important elements ensures selectors remain stable and easy to maintain.

3. Final Answer:

   Add unique, descriptive data-cy attributes to key elements and use them in tests. -> Option D

4. Quick Check:

   Unique descriptive attributes = Add unique, descriptive data-cy attributes to key elements and use them in tests. [OK]

Hint: Use clear, unique data-cy names for stable tests [OK]

Common Mistakes:

• Adding attributes only to buttons
• Relying on CSS classes that may change
• Using random values that break selectors