File upload (cy.selectFile) in Cypress - Build an Automation Script

Upload a file using the file input and verify upload success message

Preconditions (2)

Step 1: Locate the file input element with id 'file-upload'

Step 2: Use the file selector to choose 'sample.txt' from fixtures

Step 3: Click the submit button with id 'upload-submit'

Step 4: Wait for the upload success message to appear with id 'upload-success'

✅ Expected Result: The upload success message displays text 'File uploaded successfully!'

Automation Requirements - Cypress

Assertions Needed:

Verify the file input contains the selected file

Verify the success message is visible and contains correct text

Best Practices:

Use cy.selectFile() to simulate file selection

Use data-cy or id selectors for stable element targeting

Use cy.get() with assertions for visibility and content

Avoid hardcoded waits; rely on Cypress automatic waits

Automated Solution

Cypress

describe('File Upload Test', () => {
  beforeEach(() => {
    cy.visit('/upload');
  });

  it('uploads a file and verifies success message', () => {
    // Select the file input and attach the file
    cy.get('#file-upload').selectFile('cypress/fixtures/sample.txt');

    // Verify the file input has the file selected
    cy.get('#file-upload').then(input => {
      expect(input[0].files[0].name).to.equal('sample.txt');
    });

    // Click the upload button
    cy.get('#upload-submit').click();

    // Verify the success message appears with correct text
    cy.get('#upload-success')
      .should('be.visible')
      .and('contain.text', 'File uploaded successfully!');
  });
});

The test starts by visiting the upload page before each test.

It uses cy.get('#file-upload').selectFile() to simulate selecting the file sample.txt from the fixtures folder.

Then it asserts the file input element actually contains the selected file by checking the file name.

Next, it clicks the upload button to submit the file.

Finally, it verifies the success message is visible and contains the expected text, confirming the upload succeeded.

This approach uses Cypress best practices: stable selectors, no hard waits, and clear assertions.

Common Mistakes - 3 Pitfalls

Using hardcoded waits like cy.wait(5000) after clicking upload

Using CSS selectors that are brittle like complex nth-child or class names that change

{'mistake': 'Not verifying the file input contains the selected file before submitting', 'why_bad': 'The test might pass without actually selecting the file, missing a key step.', 'correct_approach': "Assert the file input's files property to confirm the file is selected."}

Bonus Challenge

Now add data-driven testing to upload three different files: 'sample.txt', 'image.png', and 'document.pdf', verifying success for each.

Show Hint

Practice

1. What is the primary purpose of cy.selectFile in Cypress testing?

easy

A. To simulate a user selecting a file for upload in a test

B. To download files from the server during a test

C. To delete files from the local system during a test

D. To open a file in the browser for viewing

Solution

1. Step 1: Understand the role of cy.selectFile

   This command is designed to simulate a user action of selecting a file in a file input element during automated tests.

2. Step 2: Compare options with this purpose

   Options B, C, and D describe actions unrelated to file selection for upload, such as downloading, deleting, or opening files, which cy.selectFile does not do.

3. Final Answer:

   To simulate a user selecting a file for upload in a test -> Option A

4. Quick Check:

   File selection = Simulate user upload [OK]

Hint: Remember: selectFile mimics user file selection [OK]

Common Mistakes:

• Confusing file upload with file download
• Thinking selectFile deletes files
• Assuming selectFile opens files in browser

2. Which of the following is the correct syntax to select a file named example.txt using cy.selectFile?

easy

A. cy.get('input[type=file]').selectFile('example.txt')

B. cy.get('input[type=file]').selectFile({ contents: 'example.txt' })

C. cy.get('input[type=file]').selectFile('file://example.txt')

D. cy.get('input[type=file]').selectFile('cypress/fixtures/example.txt')

Solution

1. Step 1: Understand file path usage in cy.selectFile

   The file path should point to the test fixture location, usually inside the cypress/fixtures folder.

2. Step 2: Evaluate each option's path

   cy.get('input[type=file]').selectFile('cypress/fixtures/example.txt') correctly uses the relative path to the fixture file. cy.get('input[type=file]').selectFile('example.txt') uses just the filename without path, which won't work. cy.get('input[type=file]').selectFile({ contents: 'example.txt' }) incorrectly uses an object with contents as string. cy.get('input[type=file]').selectFile('file://example.txt') uses an invalid file URI.

3. Final Answer:

   cy.get('input[type=file]').selectFile('cypress/fixtures/example.txt') -> Option D

4. Quick Check:

   Use fixture path for selectFile [OK]

Hint: Use fixture folder path for files in selectFile [OK]

Common Mistakes:

• Using only filename without path
• Passing file contents as string instead of path
• Using invalid file URI scheme

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

cy.get('input[type=file]').selectFile('cypress/fixtures/photo.png')
  .should('have.prop', 'files').then(files => {
    expect(files[0].name).to.equal('photo.png')
  })

medium

A. The test will pass because the file name matches

B. The test will fail because the file input does not have files property

C. The test will throw a syntax error due to incorrect chaining

D. The test will pass but the file name will be undefined

Solution

1. Step 1: Understand selectFile and file input properties

   After selecting a file, the input element's files property contains the selected files. Accessing files[0].name should give the file name.

2. Step 2: Analyze the assertion

   The assertion checks if the first file's name equals 'photo.png', which matches the selected file. This is valid and should pass.

3. Final Answer:

   The test will pass because the file name matches -> Option A

4. Quick Check:

   File name check = Pass [OK]

Hint: Files property holds selected files; check name to verify [OK]

Common Mistakes:

• Assuming files property is missing
• Confusing syntax chaining in Cypress
• Expecting undefined file name

4. You wrote this Cypress test to upload a file but it fails:

cy.get('#fileInput').selectFile('example.pdf')

What is the most likely reason for the failure?

medium

A. The selector '#fileInput' is invalid syntax

B. The file path is incorrect or missing the fixture folder

C. selectFile cannot be used on input elements

D. The file must be uploaded manually, not via tests

Solution

1. Step 1: Check file path requirements for selectFile

   The file path must be relative to the cypress/fixtures folder or an absolute path. Just 'example.pdf' without path likely causes failure.

2. Step 2: Verify other options

   Selector syntax '#fileInput' is valid. selectFile works on input elements. Manual upload is not required in tests.

3. Final Answer:

   The file path is incorrect or missing the fixture folder -> Option B

4. Quick Check:

   File path must include fixture folder [OK]

Hint: Always include fixture folder in file path [OK]

Common Mistakes:

• Using filename without path
• Thinking selector syntax is wrong
• Believing selectFile can't upload files

5. You want to test uploading multiple files at once using cy.selectFile. Which code snippet correctly uploads two files named doc1.pdf and image1.png located in the fixtures folder?

hard

A. cy.get('input[type=file]').selectFile({ files: ['doc1.pdf', 'image1.png'] })

B. cy.get('input[type=file]').selectFile('cypress/fixtures/doc1.pdf, cypress/fixtures/image1.png')

C. cy.get('input[type=file]').selectFile(['cypress/fixtures/doc1.pdf', 'cypress/fixtures/image1.png'])

D. cy.get('input[type=file]').selectFile(['doc1.pdf', 'image1.png'])

Solution

1. Step 1: Understand multiple file upload syntax

   cy.selectFile accepts an array of file paths to upload multiple files. Each path must be relative to the fixtures folder or absolute.

2. Step 2: Evaluate each option

   cy.get('input[type=file]').selectFile(['cypress/fixtures/doc1.pdf', 'cypress/fixtures/image1.png']) correctly provides an array with full fixture paths. cy.get('input[type=file]').selectFile('cypress/fixtures/doc1.pdf, cypress/fixtures/image1.png') uses a single string with comma-separated paths, which is invalid. cy.get('input[type=file]').selectFile({ files: ['doc1.pdf', 'image1.png'] }) uses an object with files array but missing paths. cy.get('input[type=file]').selectFile(['doc1.pdf', 'image1.png']) uses array without fixture folder path, which will fail.

3. Final Answer:

   cy.get('input[type=file]').selectFile(['cypress/fixtures/doc1.pdf', 'cypress/fixtures/image1.png']) -> Option C

4. Quick Check:

   Array of fixture paths = Correct multiple upload [OK]

Hint: Use array of full fixture paths for multiple files [OK]

Common Mistakes:

• Passing comma-separated string instead of array
• Omitting fixture folder in paths
• Using object without correct file paths