CSS assertions in Cypress - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ assertion

intermediate

Check background color of a button

You want to verify that a button with id #submitBtn has a background color of rgb(0, 128, 0). Which Cypress assertion is correct?

Cypress

cy.get('#submitBtn').should('have.css', 'background-color', 'rgb(0, 128, 0)')

A cy.get('#submitBtn').should('have.style', 'background-color', 'rgb(0, 128, 0)')

B cy.get('#submitBtn').should('have.css', 'background-color', 'rgb(0, 128, 0)')

C cy.get('#submitBtn').should('have.attr', 'background-color', 'rgb(0, 128, 0)')

D )')0 ,821 ,0(bgr' ,'roloc-dnuorgkcab' ,'ssc.evah'(dluohs.)'ntBtimbus#'(teg.yc

💡 Hint

Use the correct assertion method to check CSS properties.

The correct Cypress assertion to check CSS properties is 'have.css'. Option B uses it correctly. Option B uses 'css' which is not a valid assertion. Option B tries to check an attribute which is incorrect for CSS properties. Option B uses 'have.style' which is not a valid Cypress assertion.

❓ assertion

intermediate

Verify font size of a paragraph

Which Cypress command correctly asserts that a paragraph with class .intro has a font size of 16px?

Cypress

cy.get('.intro').should('have.css', 'font-size', '16px')

A cy.get('.intro').should('have.css', 'font-size', '16px')

B cy.get('.intro').should('have.attr', 'font-size', '16px')

C cy.get('.intro').should('contain.css', 'font-size', '16px')

D cy.get('.intro').should('have.style', 'font-size', '16px')

💡 Hint

Remember CSS properties are checked with 'have.css' in Cypress.

Option A correctly uses 'have.css' to check the font size. Option A incorrectly uses 'have.attr' which checks HTML attributes, not CSS. Option A uses 'contain.css' which is not a valid assertion. Option A uses 'have.style' which is invalid in Cypress.

❓ Predict Output

advanced

Output of CSS color assertion failure

What will be the test result when running this Cypress code if the element's color is rgb(255, 0, 0) but the assertion expects rgb(0, 0, 255)?

Cypress

cy.get('.title').should('have.css', 'color', 'rgb(0, 0, 255)')

A Test fails with a syntax error in the test code

B Test passes because color values are case-insensitive

C Test fails with an assertion error showing expected 'rgb(0, 0, 255)' but found 'rgb(255, 0, 0)'

D Test passes but logs a warning about color mismatch

💡 Hint

Think about what happens when expected and actual CSS values differ.

Cypress assertions compare exact CSS values. Since the actual color is red (rgb(255, 0, 0)) but the test expects blue (rgb(0, 0, 255)), the test fails with an assertion error showing the mismatch. There is no syntax error or warning in this case.

❓ locator

advanced

Best locator for CSS assertion on a disabled button

You want to assert the opacity of a disabled button. Which locator is best to select the disabled button for CSS assertion?

A cy.get('button:disabled')

B cy.get('button[disabled="true"]')

C cy.get('button.disabled')

D cy.get('button[disabled]')

💡 Hint

Consider how HTML disabled attribute works and how to select it in CSS.

Option D correctly selects buttons with the disabled attribute regardless of its value. Option D uses the :disabled pseudo-class which works but is less explicit in Cypress selectors. Option D looks for disabled="true" which is incorrect because disabled attribute is boolean and usually has no value or empty. Option D selects buttons with class 'disabled' which is different from the disabled attribute.

❓ framework

expert

Handling dynamic CSS changes in Cypress tests

You have a button that changes its background color from rgb(255, 0, 0) to rgb(0, 255, 0) after a click. Which Cypress code correctly asserts this dynamic CSS change?

A cy.get('#colorBtn').should('have.css', 'background-color', 'rgb(255, 0, 0)').click().should('have.css', 'background-color', 'rgb(0, 255, 0)')

B cy.get('#colorBtn').click().should('have.css', 'background-color', 'rgb(0, 255, 0)')

C cy.get('#colorBtn').click(); cy.get('#colorBtn').should('have.css', 'background-color', 'rgb(0, 255, 0)')

D cy.get('#colorBtn').click().then(() => { cy.get('#colorBtn').should('have.css', 'background-color', 'rgb(0, 255, 0)') })

💡 Hint

Check the initial state before click and then the changed state after click.

Option A first asserts the initial background color, then clicks, then asserts the changed color. This ensures the test checks both states clearly. Option A only checks after click, missing initial state. Option A separates commands but may cause timing issues. Option A uses then callback unnecessarily and may cause flaky tests.

Practice

1. What does the Cypress command cy.get('button').should('have.css', 'color', 'rgb(255, 0, 0)') check?

easy

A. It checks if the button is clickable.

B. It checks if the button's text color is red.

C. It checks if the button has a red background.

D. It checks if the button is visible on the page.

Solution

1. Step 1: Understand the CSS property being checked

   The command checks the CSS property 'color', which controls the text color of the element.

2. Step 2: Interpret the value 'rgb(255, 0, 0)'

   This RGB value represents the color red.

3. Final Answer:

   It checks if the button's text color is red. -> Option B

4. Quick Check:

   CSS property 'color' = text color [OK]

Hint: Check the CSS property name to know what style is tested [OK]

Common Mistakes:

• Confusing 'color' with 'background-color'
• Assuming it checks visibility instead of style
• Mixing RGB values with hex codes incorrectly

2. Which of the following is the correct Cypress syntax to assert that an element has a font size of 16 pixels?

easy

A. cy.get('p').should('css', 'font-size', '16px')

B. cy.get('p').should('have.style', 'font-size', '16px')

C. cy.get('p').assert('font-size', '16px')

D. cy.get('p').should('have.css', 'font-size', '16px')

Solution

1. Step 1: Identify the correct assertion method

   The correct Cypress assertion to check CSS is should('have.css', property, value).

2. Step 2: Match the syntax with the options

   cy.get('p').should('have.css', 'font-size', '16px') uses should('have.css', 'font-size', '16px'), which is correct syntax.

3. Final Answer:

   cy.get('p').should('have.css', 'font-size', '16px') -> Option D

4. Quick Check:

   Use should('have.css') for CSS assertions [OK]

Hint: Use 'should' with 'have.css' for CSS property checks [OK]

Common Mistakes:

• Using 'should' without 'have.css'
• Using 'assert' which is not a Cypress command
• Confusing 'have.style' with 'have.css'

3. Given the following Cypress code snippet, what will be the test result if the element's background color is actually 'rgb(0, 128, 0)'?

cy.get('.alert').should('have.css', 'background-color', 'rgb(255, 0, 0)')

medium

A. The test will fail because the background color does not match 'rgb(255, 0, 0)'.

B. The test will pass because the element has a background color.

C. The test will throw a syntax error.

D. The test will be skipped automatically.

Solution

1. Step 1: Understand the expected CSS value

   The test expects the background color to be 'rgb(255, 0, 0)', which is red.

2. Step 2: Compare with actual CSS value

   The actual background color is 'rgb(0, 128, 0)', which is green, so it does not match.

3. Final Answer:

   The test will fail because the background color does not match 'rgb(255, 0, 0)'. -> Option A

4. Quick Check:

   CSS value mismatch causes test failure [OK]

Hint: Match exact CSS values to avoid test failures [OK]

Common Mistakes:

• Assuming any color presence passes the test
• Confusing RGB values for different colors
• Expecting Cypress to auto-correct CSS mismatches

4. Identify the error in this Cypress CSS assertion and choose the fix:

cy.get('#header').should('have.css', 'font-weight', 700)

medium

A. The font-weight value should be a string: '700'.

B. The selector '#header' is invalid and should be '.header'.

C. The method 'have.css' should be replaced with 'css'.

D. The assertion should use 'expect' instead of 'should'.

Solution

1. Step 1: Check the type of CSS value in assertion

   Cypress expects the CSS value as a string, so 700 should be '700'.

2. Step 2: Verify other parts of the command

   The selector '#header' is valid, and 'should' with 'have.css' is correct syntax.

3. Final Answer:

   The font-weight value should be a string: '700'. -> Option A

4. Quick Check:

   CSS values must be strings in assertions [OK]

Hint: Always quote CSS values in Cypress assertions [OK]

Common Mistakes:

• Passing numbers instead of strings for CSS values
• Changing valid selectors unnecessarily
• Confusing assertion methods in Cypress

5. You want to verify that a button with class .submit-btn has a border radius of 5 pixels and a background color that is not transparent. Which Cypress code correctly asserts both styles?

hard

A. cy.get('.submit-btn').should('have.css', 'border-radius', '5px').and('have.css', 'background-color').not('transparent')

B. cy.get('.submit-btn').should('have.css', 'border-radius', '5px').and('have.css', 'background-color', 'rgba(0, 0, 0, 0)')

C. cy.get('.submit-btn').should('have.css', 'border-radius', '5px').and('have.css', 'background-color').should(value => expect(value).not.to.equal('rgba(0, 0, 0, 0)'))

D. cy.get('.submit-btn').should('have.css', 'border-radius', 5).and('have.css', 'background-color', 'transparent')"

Solution

1. Step 1: Assert border-radius with correct value and type

   Use should('have.css', 'border-radius', '5px') to check border radius as a string with units.

2. Step 2: Assert background-color is not transparent

   Since 'transparent' can be represented as 'rgba(0, 0, 0, 0)', use a callback assertion to check the value is not equal to that.

3. Step 3: Review options for correctness

   cy.get('.submit-btn').should('have.css', 'border-radius', '5px').and('have.css', 'background-color').should(value => expect(value).not.to.equal('rgba(0, 0, 0, 0)')) uses a callback with should and expect to verify background-color is not transparent, which is correct.

4. Final Answer:

   cy.get('.submit-btn').should('have.css', 'border-radius', '5px').and('have.css', 'background-color').should(value => expect(value).not.to.equal('rgba(0, 0, 0, 0)')) -> Option C

5. Quick Check:

   Use callback assertions for negative CSS checks [OK]

Hint: Use callback assertions to check CSS values are not equal [OK]

Common Mistakes:

• Passing numeric values without units for CSS properties
• Trying to chain 'not' directly after 'have.css' without callback
• Checking for exact transparent string instead of rgba value