Percy integration basics in Cypress

Introduction

Percy helps you catch visual changes in your app by taking screenshots during tests. It makes sure your app looks right after updates.

When you want to check if UI changes break the design.

When you update styles or layout and want to confirm nothing else changed.

When you add new features and want to see how they look visually.

When you want automated visual checks alongside your functional tests.

Syntax

Cypress

cy.percySnapshot('snapshot-name')

Use cy.percySnapshot() inside your Cypress test to take a visual snapshot.

The snapshot name helps you identify the screenshot in Percy dashboard.

Examples

Takes a snapshot of the homepage after loading it.

Cypress

cy.visit('https://example.com')
cy.percySnapshot('Homepage')

Takes a snapshot after clicking a button to check UI changes.

Cypress

cy.get('button').click()
cy.percySnapshot('After button click')

Sample Program

This test visits the homepage and takes a Percy snapshot named 'Homepage'. Percy will compare this snapshot with previous ones to find visual differences.

Cypress

describe('Visual test with Percy', () => {
  it('checks homepage appearance', () => {
    cy.visit('https://example.com')
    cy.percySnapshot('Homepage')
  })
})

Important Notes

Make sure Percy is installed and configured in your Cypress project before using cy.percySnapshot().

Snapshots are uploaded to Percy service, so you need internet connection during test runs.

Use meaningful snapshot names to easily track visual changes in Percy dashboard.

Summary

Percy integration lets you catch visual bugs by taking screenshots during Cypress tests.

Use cy.percySnapshot('name') to capture snapshots at any test step.

Review visual changes in Percy dashboard to keep your app looking great.

Practice

1. What is the main purpose of integrating Percy with Cypress tests?

easy

A. To speed up test execution time

B. To catch visual bugs by taking screenshots during tests

C. To generate test data automatically

D. To write unit tests for backend APIs

Solution

1. Step 1: Understand Percy's role in testing

   Percy is used to capture screenshots during tests to detect visual changes.

2. Step 2: Compare options with Percy's purpose

   Only To catch visual bugs by taking screenshots during tests matches Percy's function of catching visual bugs via screenshots.

3. Final Answer:

   To catch visual bugs by taking screenshots during tests -> Option B

4. Quick Check:

   Percy purpose = Visual bug detection [OK]

Hint: Percy = visual snapshots during tests [OK]

Common Mistakes:

• Thinking Percy speeds up tests
• Confusing Percy with test data tools
• Assuming Percy writes backend tests

2. Which of the following is the correct syntax to take a Percy snapshot in a Cypress test?

easy

A. percy.cySnapshot('Homepage')

B. cy.snapshotPercy('Homepage')

C. cy.percySnapshot('Homepage')

D. cy.takePercySnapshot('Homepage')

Solution

1. Step 1: Recall Percy snapshot command syntax

   The correct command is cy.percySnapshot('name') to capture snapshots.

2. Step 2: Match options with correct syntax

   Only cy.percySnapshot('Homepage') matches the exact syntax cy.percySnapshot('Homepage').

3. Final Answer:

   cy.percySnapshot('Homepage') -> Option C

4. Quick Check:

   Correct Percy command = cy.percySnapshot() [OK]

Hint: Look for exact cy.percySnapshot() syntax [OK]

Common Mistakes:

• Swapping method and object order
• Adding extra words like 'take'
• Using wrong method names

3. Given this Cypress test snippet with Percy integration:

describe('Visual test', () => {
  it('checks homepage', () => {
    cy.visit('/')
    cy.percySnapshot('Homepage loaded')
    cy.get('#login').click()
    cy.percySnapshot('Login clicked')
  })
})

How many Percy snapshots will be captured during this test run?

medium

A. 1

B. 3

C. 0

D. 2

Solution

1. Step 1: Count cy.percySnapshot calls in the test

   There are two calls: one after visiting homepage, one after clicking login.

2. Step 2: Confirm each call triggers a snapshot

   Each cy.percySnapshot() call captures one snapshot, so total is 2.

3. Final Answer:

   2 -> Option D

4. Quick Check:

   Number of snapshots = 2 [OK]

Hint: Count cy.percySnapshot() calls in test [OK]

Common Mistakes:

• Counting only one snapshot
• Assuming snapshots auto-capture without calls
• Confusing clicks with snapshots

4. You wrote this Cypress test with Percy snapshot:

it('checks page', () => {
  cy.visit('/page')
  cy.percySnapshot()
})

But Percy dashboard shows no snapshots. What is the likely problem?

medium

A. Missing snapshot name argument in cy.percySnapshot()

B. cy.visit() must be called after cy.percySnapshot()

C. Percy snapshots only work on mobile viewport

D. You must call cy.percySnapshot() twice per test

Solution

1. Step 1: Check cy.percySnapshot usage

   The cy.percySnapshot() command requires a name string argument to identify the snapshot.

2. Step 2: Identify missing argument issue

   Since no name is given, Percy does not capture or upload the snapshot.

3. Final Answer:

   Missing snapshot name argument in cy.percySnapshot() -> Option A

4. Quick Check:

   Snapshot name required = true [OK]

Hint: Always provide a name string to cy.percySnapshot() [OK]

Common Mistakes:

• Thinking visit order matters
• Believing Percy only works on mobile
• Assuming multiple snapshots are mandatory

5. You want to test a form with Percy snapshots at three steps: before filling, after filling, and after submission. Which code snippet correctly integrates Percy snapshots in Cypress?

hard

A. cy.visit('/form')
cy.percySnapshot('Before filling')
cy.get('#input').type('data')
cy.percySnapshot('After filling')
cy.get('#submit').click()
cy.percySnapshot('After submission')

B. cy.visit('/form')
cy.percySnapshot()
cy.get('#input').type('data')
cy.percySnapshot()
cy.get('#submit').click()
cy.percySnapshot()

C. cy.visit('/form')
cy.get('#input').type('data')
cy.percySnapshot('After filling')
cy.get('#submit').click()

D. cy.visit('/form')
cy.get('#submit').click()
cy.percySnapshot('After submission')

Solution

1. Step 1: Identify required Percy snapshots

   Snapshots needed at three steps: before filling, after filling, after submission.

2. Step 2: Check which snippet has all three snapshots with names

   Only cy.visit('/form') cy.percySnapshot('Before filling') cy.get('#input').type('data') cy.percySnapshot('After filling') cy.get('#submit').click() cy.percySnapshot('After submission') has three named cy.percySnapshot() calls at correct steps.

3. Final Answer:

   Code snippet with three named Percy snapshots at correct steps -> Option A

4. Quick Check:

   Three named snapshots = cy.visit('/form') cy.percySnapshot('Before filling') cy.get('#input').type('data') cy.percySnapshot('After filling') cy.get('#submit').click() cy.percySnapshot('After submission') [OK]

Hint: Name each snapshot and place at correct test steps [OK]

Common Mistakes:

• Omitting snapshot names
• Missing snapshots at required steps
• Calling snapshots before visit