Responsive breakpoint testing in Cypress - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the viewport width after this Cypress command?

Consider the following Cypress test code snippet that sets the viewport size. What will be the width of the viewport after running this command?

Cypress

cy.viewport(768, 1024);

A 375 pixels

B 1024 pixels

C 800 pixels

D 768 pixels

💡 Hint

The first number in cy.viewport(width, height) is the width in pixels.

The cy.viewport command takes width as the first argument and height as the second. So cy.viewport(768, 1024) sets the viewport width to 768 pixels.

❓ assertion

intermediate

Which assertion correctly checks if the viewport width is 375px?

You want to write a Cypress assertion to verify the viewport width is exactly 375 pixels. Which option is correct?

A cy.window().its('innerWidth').should('eq', 375);

B cy.viewport().should('have.width', 375);

C cy.get('body').should('have.css', 'width', '375px');

D cy.document().should('have.property', 'width', 375);

💡 Hint

The window object has the innerWidth property representing viewport width.

cy.window() gets the window object, and its('innerWidth') accesses the viewport width. The assertion checks if it equals 375.

🔧 Debug

advanced

Why does this test fail on mobile viewport?

This Cypress test fails when run with cy.viewport('iphone-6'). What is the most likely reason?

Cypress

cy.viewport('iphone-6');
cy.get('.menu').should('be.visible');

A The '.menu' element is hidden by default on small screens and requires a button click to show.

B The 'iphone-6' viewport preset is invalid and causes viewport size to be zero.

C The '.menu' selector is incorrect and does not match any element.

D Cypress cannot simulate mobile devices and always uses desktop viewport.

💡 Hint

Menus often collapse into a hamburger icon on small screens.

On small viewports like iPhone 6, menus are often hidden and toggled by a button. The test fails because it expects the menu visible without clicking the toggle.

❓ framework

advanced

Which Cypress command sets viewport to simulate a tablet in landscape mode?

You want to test your app on a tablet device in landscape orientation using Cypress. Which command correctly sets this viewport?

A cy.viewport(768, 1024);

B cy.viewport('ipad-2', 'portrait');

C cy.viewport('ipad-2', 'landscape');

D cy.viewport('tablet', 'landscape');

💡 Hint

Cypress supports device presets with optional orientation argument.

The 'ipad-2' preset with 'landscape' orientation sets the viewport to tablet landscape size.

🧠 Conceptual

expert

Why is testing multiple breakpoints important in responsive testing?

In responsive testing, why should you test your web app at multiple viewport widths instead of just one?

A Because testing one viewport width automatically covers all others due to CSS inheritance.

B Because different viewport widths trigger different CSS breakpoints that change layout and functionality.

C Because viewport width does not affect layout, only device type matters.

D Because Cypress requires multiple viewport sizes to run tests successfully.

💡 Hint

Think about how websites change layout on phones, tablets, and desktops.

Websites use CSS breakpoints to adjust layout and features based on viewport width. Testing multiple widths ensures all layouts work correctly.

Practice

1. What is the main purpose of using cy.viewport() in Cypress tests?

easy

A. To capture screenshots of the current page

B. To speed up test execution by skipping UI rendering

C. To mock API responses during tests

D. To simulate different screen sizes for responsive testing

Solution

1. Step 1: Understand cy.viewport() role

   cy.viewport() changes the browser size to simulate devices.

2. Step 2: Identify its use in responsive testing

   This helps check if UI adapts correctly on phones, tablets, and desktops.

3. Final Answer:

   To simulate different screen sizes for responsive testing -> Option D

4. Quick Check:

   cy.viewport() = simulate screen sizes [OK]

Hint: Remember: viewport changes screen size for layout checks [OK]

Common Mistakes:

• Confusing viewport with API mocking
• Thinking it speeds up tests by skipping UI
• Assuming it captures screenshots

2. Which of the following is the correct syntax for the iPhone 6 viewport preset in Cypress?

easy

A. cy.viewport('iphone-6')

B. cy.viewport(375, 667)

C. cy.viewport('iPhone6')

D. cy.setViewport('iphone-6')

Solution

1. Step 1: Recall Cypress viewport presets

   Cypress supports device names like 'iphone-6' in cy.viewport().

2. Step 2: Check syntax correctness

   cy.viewport('iphone-6') uses correct method and exact device name string.

3. Final Answer:

   cy.viewport('iphone-6') -> Option A

4. Quick Check:

   Correct device name string in cy.viewport() [OK]

Hint: Use exact device names in quotes with cy.viewport() [OK]

Common Mistakes:

• Using wrong method name like cy.setViewport()
• Incorrect device name casing or spelling
• Passing numbers without quotes for presets

3. What will be the result of this Cypress test snippet?

cy.viewport('ipad-2')
cy.get('.menu').should('be.visible')

medium

A. Test ignores viewport and checks .menu visibility on default size

B. Test passes if .menu is visible on iPad 2 screen size

C. Test throws syntax error due to missing semicolon

D. Test fails because 'ipad-2' is not a valid viewport preset

Solution

1. Step 1: Understand viewport preset 'ipad-2'

   'ipad-2' is a valid Cypress preset simulating iPad 2 screen size.

2. Step 2: Analyze assertion behavior

   The test checks if element with class .menu is visible at that size.

3. Final Answer:

   Test passes if .menu is visible on iPad 2 screen size -> Option B

4. Quick Check:

   Valid preset + visibility check = pass if visible [OK]

Hint: Valid preset means viewport changes; assertion checks visibility [OK]

Common Mistakes:

• Thinking 'ipad-2' is invalid preset
• Assuming missing semicolons cause errors in Cypress
• Believing viewport is ignored without explicit reload

4. Identify the error in this Cypress test for responsive breakpoint:

cy.viewport(1024, 768)
cy.get('#nav').should('be.visible')
cy.viewport('mobile')
cy.get('#nav').should('not.be.visible')

medium

A. Incorrect selector '#nav' should be '.nav'

B. Missing wait between viewport changes causes flaky test

C. Invalid viewport preset 'mobile' causes test failure

D. Assertions are reversed; nav should be visible on mobile

Solution

1. Step 1: Check viewport presets used

   1024x768 is valid, but 'mobile' is not a recognized preset in Cypress.

2. Step 2: Understand impact of invalid preset

   Using 'mobile' causes Cypress to throw an error and fail the test.

3. Final Answer:

   Invalid viewport preset 'mobile' causes test failure -> Option C

4. Quick Check:

   Use only valid viewport presets [OK]

Hint: Use only Cypress documented viewport presets [OK]

Common Mistakes:

• Assuming 'mobile' is a valid preset
• Thinking missing waits cause failure here
• Confusing selector correctness with viewport issues

5. You want to test a web page's header visibility on desktop (1440x900) and mobile (375x667). Which is the best Cypress test approach?

hard

A. Write two separate tests using cy.viewport(1440, 900) and cy.viewport(375, 667) with visibility assertions

B. Write one test with cy.viewport(1440, 900) only, assuming mobile works the same

C. Use cy.viewport('iphone-x') only, ignoring desktop size

D. Test only on default viewport size without changing viewport

Solution

1. Step 1: Understand responsive testing goal

   We want to verify header visibility on both desktop and mobile screen sizes.

2. Step 2: Choose best Cypress approach

   Writing separate tests with explicit viewport sizes ensures coverage of both layouts.

3. Final Answer:

   Write two separate tests using cy.viewport(1440, 900) and cy.viewport(375, 667) with visibility assertions -> Option A

4. Quick Check:

   Separate viewport tests cover all breakpoints [OK]

Hint: Test each breakpoint separately for reliable responsive checks [OK]

Common Mistakes:

• Assuming one viewport size covers all devices
• Ignoring desktop or mobile viewport testing
• Relying on default viewport without changes