File download verification in Cypress - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Verify file download success with Cypress

What will be the result of this Cypress test code when verifying a file download?

Cypress

cy.downloadFile('https://example.com/report.pdf', 'cypress/downloads', 'report.pdf')
  .then(() => {
    cy.readFile('cypress/downloads/report.pdf').should('have.length.above', 0)
  })

A Test fails because cy.readFile cannot read PDF files

B Test passes but file content is not verified

C Test fails due to syntax error in chaining

D Test passes because the file is downloaded and exists in the folder

💡 Hint

cy.readFile can check if a file exists after download

The code downloads the file and then checks if it exists in the downloads folder. This confirms the download succeeded.

❓ assertion

intermediate

Correct assertion to verify downloaded file content

Which assertion correctly verifies that the downloaded text file contains the word 'Success'?

Cypress

cy.readFile('cypress/downloads/result.txt').should(____)

A "have.text", "Success"

B "contain", "Success"

C "include", "Success"

D "include.text", "Success"

💡 Hint

Use the correct Cypress string assertion for substring matching

The 'contain' assertion checks if the file content includes the given substring.

🔧 Debug

advanced

Identify the error in this file download test

Why does this Cypress test fail to verify the downloaded file?

Cypress

cy.get('#download-btn').click()
cy.readFile('cypress/downloads/report.pdf').should('have.length.above', 0)

A cy.readFile cannot read PDF files

B The selector '#download-btn' is invalid

C The test does not wait for the download to complete before reading the file

D The file path is incorrect

💡 Hint

Downloads may take time; reading file immediately can fail

The test tries to read the file immediately after clicking download, but the file may not be fully saved yet.

🧠 Conceptual

advanced

Best practice for verifying file downloads in Cypress

Which approach is best to verify a file download in Cypress tests?

A Intercept the download request and check the response headers and body

B Click download button and immediately check file existence in downloads folder

C Use cy.readFile to read the file before clicking download

D Check the UI message that says 'Download started' without checking the file

💡 Hint

Intercepting network requests gives more control and certainty

Intercepting the download request allows verifying the actual file content and status before checking the file system.

❓ framework

expert

Implementing a custom Cypress command for file download verification

Which custom Cypress command implementation correctly waits for a file to be downloaded and verifies its existence?

Cypress

Cypress.Commands.add('verifyDownload', (fileName) => {
  const downloadsFolder = Cypress.config('downloadsFolder')
  cy.readFile(`${downloadsFolder}/${fileName}`, { timeout: 15000 }).should('have.length.above', 0)
})

A The command waits up to 15 seconds for the file to exist and asserts its presence

B The command immediately reads the file without waiting, causing flaky tests

C The command uses incorrect path syntax causing a runtime error

D The command only checks file size but not existence

💡 Hint

Use timeout option in cy.readFile to wait for file

Setting a timeout in cy.readFile allows waiting for the file to appear before asserting existence.

Practice

1. What is the main purpose of file download verification in Cypress testing?

easy

A. To speed up the test execution time

B. To ensure the downloaded file is correct and complete

C. To check the website's loading speed

D. To verify the page layout after download

Solution

1. Step 1: Understand file download verification

   File download verification checks if the file users get is the right one and fully downloaded.

2. Step 2: Identify the main goal

   The goal is to confirm the file content and completeness, not speed or layout.

3. Final Answer:

   To ensure the downloaded file is correct and complete -> Option B

4. Quick Check:

   File correctness = B [OK]

Hint: File download verification checks file correctness, not speed [OK]

Common Mistakes:

• Confusing download verification with page speed testing
• Thinking it checks page layout after download
• Assuming it speeds up tests

2. Which Cypress command is used to read the contents of a downloaded file for verification?

easy

A. cy.readFile()

B. cy.getFile()

C. cy.downloadFile()

D. cy.checkFile()

Solution

1. Step 1: Identify commands related to file handling

   cy.downloadFile() downloads files, cy.readFile() reads file contents.

2. Step 2: Choose the command to read file contents

   To verify file content, cy.readFile() is used, not cy.downloadFile().

3. Final Answer:

   cy.readFile() -> Option A

4. Quick Check:

   Read file = cy.readFile() = A [OK]

Hint: Use cy.readFile() to check file content after download [OK]

Common Mistakes:

• Using cy.downloadFile() to read file content
• Assuming cy.getFile() exists
• Confusing cy.checkFile() with real commands

3. Given the code snippet:

cy.downloadFile('https://example.com/report.pdf', 'cypress/downloads', 'report.pdf')
  .then(() => {
    cy.readFile('cypress/downloads/report.pdf').should('exist')
  })

What will this test verify?

medium

A. That the downloads folder is empty before download

B. That the file 'report.pdf' is empty

C. That the URL 'https://example.com/report.pdf' is reachable

D. That the file 'report.pdf' exists in the downloads folder after download

Solution

1. Step 1: Analyze the downloadFile command

   The command downloads 'report.pdf' to 'cypress/downloads'.

2. Step 2: Analyze the readFile assertion

   It checks if 'report.pdf' exists in the downloads folder after download.

3. Final Answer:

   That the file 'report.pdf' exists in the downloads folder after download -> Option D

4. Quick Check:

   File existence check = D [OK]

Hint: Check file existence with cy.readFile().should('exist') [OK]

Common Mistakes:

• Assuming it checks file content or emptiness
• Thinking it tests URL reachability
• Confusing pre-download folder state with post-download check

4. Identify the error in this Cypress test code for file download verification:

cy.downloadFile('https://example.com/data.csv', 'cypress/downloads', 'data.csv')
cy.readFile('cypress/downloads/data.csv').should('contain', 'Name, Age')

medium

A. Wrong assertion method; should use 'exist' instead of 'contain'

B. Incorrect file path in readFile command

C. Missing chaining or waiting for download to complete before reading file

D. cy.downloadFile does not exist in Cypress

Solution

1. Step 1: Check command sequence and chaining

   The download and readFile commands run separately without waiting for download to finish.

2. Step 2: Identify the need for chaining or waiting

   Without chaining or waiting, readFile may run before download completes, causing test failure.

3. Final Answer:

   Missing chaining or waiting for download to complete before reading file -> Option C

4. Quick Check:

   Wait for download before readFile = C [OK]

Hint: Chain commands or wait to ensure download finishes before reading [OK]

Common Mistakes:

• Running readFile immediately without waiting
• Assuming cy.downloadFile is not a valid command
• Using wrong assertion method for content check

5. You want to verify that a downloaded CSV file contains the header 'ID, Name, Email' and is not empty. Which Cypress test code correctly achieves this?

hard

A. cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv')
.then(() => {
cy.readFile('cypress/downloads/users.csv').should('contain', 'ID, Name, Email').and('not.be.empty')
})

B. cy.readFile('cypress/downloads/users.csv').should('contain', 'ID, Name, Email')
cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv')

C. cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv')
cy.readFile('cypress/downloads/users.csv').should('exist')

D. cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv')
.then(() => {
cy.readFile('cypress/downloads/users.csv').should('be.empty')
})

Solution

1. Step 1: Ensure download completes before reading file

   cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv') .then(() => { cy.readFile('cypress/downloads/users.csv').should('contain', 'ID, Name, Email').and('not.be.empty') }) chains .then() after downloadFile to wait for completion.

2. Step 2: Verify file contains header and is not empty

   cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv') .then(() => { cy.readFile('cypress/downloads/users.csv').should('contain', 'ID, Name, Email').and('not.be.empty') }) uses should('contain', ...) and .and('not.be.empty') correctly to check content and non-empty file.

3. Final Answer:

   cy.downloadFile('https://example.com/users.csv', 'cypress/downloads', 'users.csv') .then(() => { cy.readFile('cypress/downloads/users.csv').should('contain', 'ID, Name, Email').and('not.be.empty') }) -> Option A

4. Quick Check:

   Chain download and readFile with content checks = A [OK]

Hint: Chain downloadFile with readFile and use should contain + not.be.empty [OK]

Common Mistakes:

• Not chaining download and readFile causing timing issues
• Checking file existence only without content validation
• Asserting file is empty instead of not empty