Parallel execution in Cypress - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Parallel Execution in Cypress

What is the main benefit of running tests in parallel in Cypress?

A It automatically fixes failing tests by retrying them infinitely.

B It disables all network requests during test execution.

C It reduces the total test execution time by running tests simultaneously on multiple machines or containers.

D It ensures tests run one after another to avoid conflicts.

💡 Hint

Think about how running multiple tasks at the same time affects total time.

Parallel execution splits tests across multiple machines or containers to run at the same time, which reduces total test time.

❓ Predict Output

intermediate

Output of Cypress Parallel Execution Command

What will be the output status of this Cypress command when running tests in parallel with 3 machines?

Cypress

npx cypress run --parallel --ci-build-id 12345 --record

// Assume tests are split evenly and all pass.

A All tests pass with a summary showing 3 machines ran tests in parallel.

B Tests run sequentially on one machine only.

C Command fails with an error about missing configuration.

D Tests run but results are not recorded or split.

💡 Hint

Look for the effect of --parallel and --record flags.

The --parallel flag enables splitting tests across machines, and --record sends results to Cypress Dashboard, showing a summary of parallel runs.

❓ assertion

advanced

Correct Assertion for Parallel Test Completion

Which assertion correctly verifies that all parallel test runs have completed successfully in Cypress Dashboard API response?

Cypress

const response = {
  status: 'completed',
  machines: 3,
  testsPassed: 45,
  testsFailed: 0
};

A expect(response.testsFailed).to.equal(1) && expect(response.status).to.equal('completed');

B expect(response.status).to.be('running') && expect(response.testsFailed).to.be(0);

C expect(response.machines).to.equal(1) && expect(response.testsPassed).to.be.greaterThan(0);

D expect(response.status).to.equal('completed') && expect(response.testsFailed).to.equal(0);

💡 Hint

Check for status 'completed' and zero failed tests.

To confirm all parallel tests finished successfully, status must be 'completed' and testsFailed must be 0.

🔧 Debug

advanced

Debugging Parallel Test Failures in Cypress

You notice that when running tests in parallel, some tests fail intermittently due to shared state issues. What is the best debugging approach?

A Isolate tests to run independently by resetting state before each test and avoid shared data.

B Run all tests sequentially to avoid parallel execution.

C Ignore failures since they happen only in parallel mode.

D Increase the number of parallel machines to reduce failures.

💡 Hint

Think about why tests might interfere with each other when run at the same time.

Shared state causes flaky tests in parallel runs. Resetting state before each test ensures isolation and reliability.

❓ framework

expert

Configuring Cypress Parallel Execution in CI

Which configuration snippet correctly enables Cypress parallel execution in a CI environment using GitHub Actions with 4 parallel jobs?

Cypress

name: Cypress Tests
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        job: [1, 2, 3, 4]
    steps:
      - uses: actions/checkout@v3
      - name: Install dependencies
        run: npm ci
      - name: Run Cypress tests in parallel
        run: |
          npx cypress run --record --parallel --ci-build-id ${{ github.run_id }}
        env:
          CYPRESS_RECORD_KEY: ${{ secrets.CYPRESS_RECORD_KEY }}

A The snippet runs Cypress tests sequentially without parallel flag and no matrix strategy.

B The snippet correctly uses matrix strategy with 4 jobs and runs Cypress with --parallel and unique ci-build-id.

C The snippet uses parallel flag but does not provide a unique ci-build-id, causing conflicts.

D The snippet runs Cypress without recording results, so parallel execution is disabled.

💡 Hint

Check for matrix jobs and unique build ID usage.

Using GitHub Actions matrix with 4 jobs and passing a unique ci-build-id enables Cypress to split tests across jobs in parallel and record results properly.