Asserting response bodies in Cypress - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ assertion

intermediate

Correct assertion for JSON response property

You have a Cypress test that sends a GET request to '/api/user'. The response body is expected to have a property 'name' with value 'Alice'. Which assertion correctly verifies this?

Cypress

cy.request('/api/user').then((response) => {
  // Insert assertion here
})

A expect(response.body.name).to.equal('Alice')

B expect(response.body.name).to.be.undefined

C expect(response.body).to.have.property('name', 'Bob')

D expect(response.status).to.equal(404)

💡 Hint

Check the property name and expected value carefully.

Option A correctly asserts that the 'name' property in the response body equals 'Alice'. Option A checks for 'Bob', which is incorrect. Option A expects the property to be undefined, which is wrong. Option A checks the status code, not the body property.

❓ Predict Output

intermediate

Output of response body assertion with nested object

What will be the result of this Cypress test snippet?

Cypress

cy.request('/api/product').then((response) => {
  expect(response.body.product.id).to.equal(123);
  expect(response.body.product.available).to.be.true;
})

A Test throws a TypeError if product property is missing

B Test fails if product id is 123 but available is false

C Test passes if product id is 123 and available is true

D Test passes regardless of response body content

💡 Hint

Consider what happens if the assertions match the response body.

The test passes only if both assertions are true: product id equals 123 and available is true. If either fails, the test fails. If product is missing, a TypeError would occur but that is not the expected normal case.

🔧 Debug

advanced

Identify the error in response body assertion

This Cypress test fails with an error. What is the cause?

Cypress

cy.request('/api/data').then((response) => {
  expect(response.body.data).to.have.length(5)
  expect(response.body.data[0]).to.equal('item1')
})

A response.body.data is not an array, so .length causes error

B Missing semicolon after first expect causes syntax error

C Using .equal instead of .deep.equal causes failure

D The URL '/api/data' is incorrect causing 404 error

💡 Hint

Check the type of response.body.data before using .length

If response.body.data is not an array, accessing .length or indexing with [0] will cause an error. The semicolon is optional in JavaScript. .equal works for string comparison. The URL correctness is not indicated by the error.

🧠 Conceptual

advanced

Best practice for asserting partial response body

You want to check that the response body contains a property 'status' with value 'success', but the body has many other properties you don't want to assert. Which is the best Cypress assertion?

A expect(response.body).to.deep.equal({status: 'success'})

B expect(response.body).to.include({status: 'success'})

C expect(response.body).to.have.length(1)

D expect(response.body.status).to.equal('success')

💡 Hint

Think about checking only one property without affecting others.

Option D directly asserts the 'status' property value without requiring the whole object to match. Option D requires exact match of the entire body, which is too strict. Option D is invalid because .include is not a valid Chai assertion for objects in this way. Option D checks length which is irrelevant.

❓ framework

expert

Handling asynchronous response body assertions in Cypress

You want to assert that a POST request to '/api/login' returns a JSON body with a token property. Which Cypress code snippet correctly waits and asserts the token exists?

A

cy.request('POST', '/api/login', {user: 'test'}).wait(1000).then((response) => {
  expect(response.body.token).to.exist
})

B

cy.request('POST', '/api/login', {user: 'test'}).then((response) => {
  expect(response.body.token).to.exist
})

C

cy.request('POST', '/api/login', {user: 'test'}).should((response) => {
  expect(response.body.token).to.exist
})

D

cy.request('POST', '/api/login', {user: 'test'}).then(() => {
  expect(response.body.token).to.exist
})

💡 Hint

Remember how Cypress handles promises and response objects.

Option B correctly uses .then() to access the response and assert the token property. Option B uses .should() which is not designed for cy.request responses. Option B adds unnecessary wait which is not needed. Option B tries to access response.body without receiving the response parameter, causing an error.

Practice

1. What is the main purpose of asserting response bodies in Cypress tests?

easy

A. To check if the UI elements are visible on the page

B. To verify the server sends the correct data in the response body

C. To measure the page load time

D. To test the browser compatibility

Solution

1. Step 1: Understand response body assertion

   Asserting response bodies means checking the data returned by the server is correct and as expected.

2. Step 2: Identify the purpose in Cypress tests

   Cypress uses assertions on response bodies to confirm the server sends the right data, not UI or performance checks.

3. Final Answer:

   To verify the server sends the correct data in the response body -> Option B

4. Quick Check:

   Response body assertion = verify server data [OK]

Hint: Response body assertions check server data, not UI or speed [OK]

Common Mistakes:

• Confusing response body with UI element checks
• Thinking it measures performance
• Assuming it tests browser features

2. Which of the following is the correct syntax to assert that the response body has a property name equal to "John" in Cypress?

easy

A. cy.request('/api/user').expect('body.name').to.equal('John')

B. cy.request('/api/user').body.should('contain', 'name', 'John')

C. cy.request('/api/user').its('body').should('have.property', 'name', 'John')

D. cy.request('/api/user').should('body.name', 'John')

Solution

1. Step 1: Review Cypress chaining syntax

   In Cypress, cy.request() returns a response object. To assert a property in the body, use its('body') to access it.

2. Step 2: Use should('have.property', key, value) for assertion

   The correct way to check a property and its value is should('have.property', 'name', 'John').

3. Final Answer:

   cy.request('/api/user').its('body').should('have.property', 'name', 'John') -> Option C

4. Quick Check:

   Use its('body').should('have.property', key, value) [OK]

Hint: Use its('body').should('have.property', key, value) for body checks [OK]

Common Mistakes:

• Trying to access body directly without its()
• Using expect() incorrectly inside cy.request chain
• Wrong method names like expect() or body.should()

3. Given the following Cypress code, what will be the result of the assertion?

cy.request('/api/data').then((response) => {
  expect(response.status).to.eq(200)
  expect(response.body.items).to.have.length(3)
})

medium

A. The test passes if the response status is 200 and items array has exactly 3 elements

B. The test fails if the response status is 200 but items array has more than 3 elements

C. The test passes regardless of the items array length

D. The test fails if the response status is not 404

Solution

1. Step 1: Analyze the status code assertion

   The code expects response.status to equal 200, so the server must respond with HTTP 200.

2. Step 2: Analyze the items array length assertion

   The code expects response.body.items to have exactly 3 elements. If it has more or less, the test fails.

3. Final Answer:

   The test passes if the response status is 200 and items array has exactly 3 elements -> Option A

4. Quick Check:

   Status 200 and items length 3 = pass [OK]

Hint: Both status and body length must match exactly for pass [OK]

Common Mistakes:

• Ignoring the length check on items array
• Confusing status 200 with 404
• Assuming partial matches pass

4. Identify the error in this Cypress test code that asserts the response body property success is true:

cy.request('/api/submit').then((response) => {
  expect(response.body.success).to.be.true()
})

medium

A. The cy.request method is missing a URL

B. The property success does not exist in response.body

C. The then callback should use response.body.success()

D. The assertion should be to.be.true without parentheses

Solution

1. Step 1: Check the assertion syntax

   In Chai assertions used by Cypress, to.be.true is a property, not a function, so it should not have parentheses.

2. Step 2: Confirm other parts are correct

   The URL is provided, and accessing response.body.success is valid if the property exists.

3. Final Answer:

   The assertion should be to.be.true without parentheses -> Option D

4. Quick Check:

   Use to.be.true without () for boolean assertions [OK]

Hint: Boolean assertions use to.be.true without parentheses [OK]

Common Mistakes:

• Adding parentheses to boolean assertions
• Assuming success is a function
• Missing URL in cy.request

5. You want to assert that the response body contains a nested object with a user's id equal to 5 and a roles array containing "admin". Which Cypress assertion correctly checks both conditions?

hard

A. cy.request('/api/user/5').its('body').should((body) => {
expect(body.id).to.eq(5)
expect(body.roles).to.include('admin')
})

B. cy.request('/api/user/5').should('body.id', 5).and('body.roles', 'admin')

C. cy.request('/api/user/5').then((response) => {
expect(response.body.id).to.equal(5)
expect(response.body.roles).to.have.length(1)
})

D. cy.request('/api/user/5').its('body').should('have.property', 'id', 5).and('have.property', 'roles', 'admin')

Solution

1. Step 1: Understand nested assertions with callback

   Using should with a callback allows multiple assertions on the body object.

2. Step 2: Check each assertion correctness

   expect(body.id).to.eq(5) checks the id correctly. expect(body.roles).to.include('admin') checks the roles array contains 'admin'.

3. Step 3: Identify incorrect options

   cy.request('/api/user/5').should('body.id', 5).and('body.roles', 'admin') uses invalid chaining syntax. cy.request('/api/user/5').then((response) => { expect(response.body.id).to.equal(5) expect(response.body.roles).to.have.length(1) }) misses checking 'admin' in roles. cy.request('/api/user/5').its('body').should('have.property', 'id', 5).and('have.property', 'roles', 'admin') wrongly checks roles as a property equal to string 'admin'.

4. Final Answer:

   cy.request('/api/user/5').its('body').should((body) => { expect(body.id).to.eq(5) expect(body.roles).to.include('admin') }) -> Option A

5. Quick Check:

   Use callback in should for multiple nested assertions [OK]

Hint: Use should callback for multiple nested property checks [OK]

Common Mistakes:

• Trying to chain multiple properties incorrectly
• Checking array length instead of content
• Using have.property with array content as string