Test Retries in Cypress

 

 What you’ll learn

• What are test retries?
• Why are test retries important?
• How to configure test retries

Introduction:-

End-to-end (E2E) tests excel at testing complex systems. However, there are still behaviors that are hard to verify and make tests flaky (i.e., unreliable) and fail sometimes due to unpredictable conditions (eg., temporary outages in external dependencies, random network errors, etc.). Some other common race conditions that could result in unreliable tests include:

• Animations
• API calls
• Test server / database availability
• Resource dependencies availability
• Network issues

With test retries, Cypress is able to retry failed tests to help reduce test flakiness and continuous integration (CI) build failures. By doing so, this will save your team valuable time and resources so you can focus on what matters most to you.

How It Works

By default, tests will not retry when they fail. You will need to enable test retries in your configuration to use this feature.

Once test retries are enabled, tests can be configured to have X number of retry attempts. For example, if test retries has been configured with 2 retry attempts, Cypress will retry tests up to 2 additional times (for a total of 3 attempts) before potentially being marked as a failed test.

When each test is run again, the following hooks will be re-run also:

• beforeEach
• afterEach

However, failures in before and after hooks will not trigger a retry.

The following is a detailed step-by-step example of how test retries works:

Assuming we have configured test retries with 2 retry attempts (for a total of 3 attempts), here is how the tests might run:

1. A test runs for the first time. If the  test passes, Cypress will move forward with any remaining tests as usual.

2. If the  test fails, Cypress will tell you that the first attempt failed and will attempt to run the test a second time.

3. If the  test passes after the second attempt, Cypress will continue with any remaining tests.

4. If the  test fails a second time, Cypress will make the final third attempt to re-run the test.

5. If the  test fails a third time, Cypress will mark the test as failed and then move on to run any remaining tests.

The following is a screen capture of what test retries looks like on the same failed test when run via cypress run.

During cypress open you will be able to see the number of attempts made in the Command Log and expand each attempt for review and debugging if desired.

Configure Test Retries:-

Global Configuration

Typically you will want to define different retry attempts for cypress run versus cypress open. You can configure this in your configuration file (cypress.json by default) by passing the retries option an object with the following options:

• runMode allows you to define the number of test retries when running cypress run
• openMode allows you to define the number of test retries when running cypress open

{
  "retries": {
    // Configure retry attempts for `cypress run`
    // Default is 0
    "runMode": 2,
    // Configure retry attempts for `cypress open`
    // Default is 0
    "openMode": 0
  }
}

Configure retry attempts for all modes

If you want to configure the retry attempts for all tests run in both cypress run and cypress open, you can configure this in your configuration file (cypress.json by default) by defining the retries property and setting the desired number of retries.

{
  "retries": 1
}

Custom Configurations

Individual Test(s)

If you want to configure retry attempts on a specific test, you can set this by using the test’s configuration.

// Customize retry attempts for an individual test
describe('User sign-up and login', () => {
  // `it` test block with no custom configuration
  it('should redirect unauthenticated user to sign-in page', () => {
    // ...
  })

  // `it` test block with custom configuration
  it('allows user to login', {
    retries: {
      runMode: 2,
      openMode: 1
    }
  }, () => {
    // ...
  })
})

Test Suite(s)

If you want to configure try attempts for a suite of tests, you can do this by setting the suite’s configuration.

// Customizing retry attempts for a suite of tests
describe('User bank accounts', {
  retries: {
    runMode: 2,
    openMode: 1,
  }
}, () => {
  // The per-suite configuration is applied to each test
  // If a test fails, it will be retried
  it('allows a user to view their transactions', () => {
    // ...
  }

  it('allows a user to edit their transactions', () => {
    // ...
  }
})

You can find more information about custom configurations here: Test Configuration

Screenshots:-

When a test retries, Cypress will continue to take screenshots for each failed attempt or cy.screenshot() and suffix each new screenshot with (attempt n), corresponding to the current retry attempt number.

With the following test code, you would see the below screenshot filenames when all 3 attempts fail:

describe('User Login', () => {
  it('displays login errors', () => {
    cy.visit('/')
    cy.screenshot('user-login-errors')
    // ...
  })
})

// screenshot filename from cy.screenshot() on 1st attempt
'user-login-errors.png'
// screenshot filename on 1st failed attempt
'user-login-errors (failed).png'
// screenshot filename from cy.screenshot() on 2nd attempt
'user-login-errors (attempt 2).png'
// screenshot filename on 2nd failed attempt
'user-login-errors (failed) (attempt 2).png'
// screenshot filename from cy.screenshot() on 3rd attempt
'user-login-errors (attempt 3).png'
// screenshot filename on 3rd failed attempt
'user-login-errors (failed) (attempt 3).png'

Dashboard:-

If you are using the Cypress Dashboard, information related to test retries is displayed on the Test Results tab for a run. Selecting the Flaky filter will show tests that retried and then passed during the run.

These tests are also indicated with a “Flaky” badge on the Latest Runs page and Test Results tab on the Run Details page.

Clicking on a Test Result will open the Test Case History screen. This demonstrates the number of failed attempts, the screenshots and/or videos of failed attempts, and the error for failed attempts.

You can also see the Flaky Rate for a given test.

For a comprehensive view of how flake is affecting your overall test suite, you can review the Flake Detection and Flake Alerting features highlighted in the Test Flake Management Guide.