Cypress CLI execution - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Cypress CLI command?

You run the command cypress run --spec cypress/e2e/login.cy.js in your terminal. What will Cypress do?

A Run all tests in the <code>login.cy.js</code> file and output results in the terminal.

B Open the Cypress Test Runner GUI and allow manual test selection.

C Run all tests in the <code>cypress/e2e</code> folder except <code>login.cy.js</code>.

D Run tests only in the <code>cypress/support</code> folder.

💡 Hint

The --spec flag specifies which test file to run in headless mode.

The cypress run command runs tests in headless mode. Using --spec limits the run to the specified test file. So, only tests in login.cy.js will run and results will show in the terminal.

❓ assertion

intermediate

Which assertion verifies Cypress CLI ran tests successfully?

After running cypress run, you want to check if all tests passed by inspecting the exit code. Which assertion is correct in a Node.js script?

Cypress

const { exec } = require('child_process');
exec('cypress run', (error, stdout, stderr) => {
  // Which assertion below correctly checks success?
});

A assert.strictEqual(error, null);

B assert.strictEqual(error.code, 1);

C assert.strictEqual(stderr.length, 0);

D assert.strictEqual(stdout.includes('failing'), true);

💡 Hint

A null error means the command exited with code 0 (success).

If error is null, the Cypress CLI command exited successfully with code 0, meaning all tests passed. Other options check for failure or incorrect conditions.

🔧 Debug

advanced

Why does cypress run --headless fail with 'No browser found' error?

You run cypress run --headless --browser chrome but get an error: No browser found named chrome. What is the most likely cause?

A You must specify the full path to the Chrome executable.

B Chrome browser is not installed or not detected on the system.

C The <code>--headless</code> flag is incompatible with Chrome.

D Cypress CLI requires <code>--browser chromium</code> instead of <code>chrome</code>.

💡 Hint

Cypress needs the browser installed to run tests in it.

The error means Cypress cannot find the Chrome browser installed on your machine. You must have Chrome installed and accessible in your system PATH for Cypress to run tests in it.

🧠 Conceptual

advanced

What does the --record flag do in Cypress CLI?

You run cypress run --record --key abc123. What is the purpose of the --record flag?

A It records video of the test run locally on your machine.

B It runs tests in parallel automatically on multiple machines.

C It enables verbose logging of all test steps in the terminal.

D It uploads test results to the Cypress Dashboard for detailed reporting.

💡 Hint

Think about Cypress Dashboard integration.

The --record flag sends test results to the Cypress Dashboard service, allowing you to see detailed reports, test history, and analytics online. It requires a valid project --key.

❓ framework

expert

In a CI pipeline, which Cypress CLI command best runs tests with video recording and fails the build on test failures?

You want to run Cypress tests in a CI environment. You want to record videos, upload results to Dashboard, and ensure the pipeline fails if any test fails. Which command is best?

A cypress run --record --key $CYPRESS_RECORD_KEY --video --exit

B cypress run --record --key $CYPRESS_RECORD_KEY --video --fail-fast

C cypress run --record --key $CYPRESS_RECORD_KEY --video

D cypress open --record --key $CYPRESS_RECORD_KEY --video

💡 Hint

Consider default Cypress CLI behavior on test failures.

The cypress run command by default exits with a non-zero code if tests fail, causing CI to fail. The --video flag enables video recording. The --record flag uploads results to Dashboard. --exit is deprecated and --fail-fast stops on first failure but is optional.

Practice

1. What does running cypress run from the command line do?

easy

A. Runs all tests in headless mode without opening the Cypress UI

B. Opens the Cypress Test Runner UI for manual test selection

C. Starts a web server for the application under test

D. Generates a test report without executing tests

Solution

1. Step 1: Understand the command cypress run

   This command runs Cypress tests from the command line without opening the UI.

2. Step 2: Identify the mode of execution

   By default, cypress run runs tests in headless mode, meaning no browser window appears.

3. Final Answer:

   Runs all tests in headless mode without opening the Cypress UI -> Option A

4. Quick Check:

   cypress run = headless test run [OK]

Hint: Remember: 'run' means headless test execution [OK]

Common Mistakes:

• Confusing 'cypress run' with 'cypress open'
• Thinking it opens the UI
• Assuming it starts a server

2. Which of the following is the correct syntax to run Cypress tests in Chrome browser using CLI?

easy

A. cypress run --browser chrome

B. cypress open --browser chrome

C. cypress run -b firefox

D. cypress start --browser chrome

Solution

1. Step 1: Identify the correct command to run tests in CLI

   cypress run is used to run tests from CLI, not cypress open or cypress start.

2. Step 2: Check the correct option for specifying browser

   The option to specify browser is --browser, so cypress run --browser chrome is correct syntax.

3. Final Answer:

   cypress run --browser chrome -> Option A

4. Quick Check:

   Use --browser with cypress run [OK]

Hint: Use 'cypress run --browser' to specify browser [OK]

Common Mistakes:

• Using 'cypress open' instead of 'cypress run' for CLI execution
• Using wrong option '-b' instead of '--browser'
• Using non-existent command 'cypress start'

3. What will be the output when running cypress run --spec "cypress/e2e/login.cy.js"?

medium

A. Runs all tests except those in login.cy.js

B. Runs only the tests inside login.cy.js and shows results in terminal

C. Opens Cypress UI and highlights login.cy.js tests

D. Throws an error because --spec is invalid

Solution

1. Step 1: Understand the --spec option

   The --spec option tells Cypress to run only the specified test file(s).

2. Step 2: Analyze the command behavior

   The command runs tests only in cypress/e2e/login.cy.js and outputs results in the terminal because cypress run is headless.

3. Final Answer:

   Runs only the tests inside login.cy.js and shows results in terminal -> Option B

4. Quick Check:

   --spec runs specified test file only [OK]

Hint: Use --spec to run specific test files [OK]

Common Mistakes:

• Thinking it runs all tests except specified file
• Expecting Cypress UI to open with 'run' command
• Assuming --spec is invalid option

4. You run cypress run --browser chrome --headed but tests still run headless. What is the likely cause?

medium

A. Cypress does not support headed mode with Chrome

B. The Chrome browser is not installed on the machine

C. The command must include --headless to run headed

D. The --headed flag is misspelled or missing

Solution

1. Step 1: Understand the --headed flag

   The --headed flag runs tests with the browser UI visible, not headless.

2. Step 2: Identify why tests run headless despite --headed

   The likely cause is that the --headed flag was misspelled (e.g., --headless) or missing from the actual command executed. cypress run defaults to headless mode without the correct flag.

3. Final Answer:

   The --headed flag is misspelled or missing -> Option D

4. Quick Check:

   Missing or misspelled --headed defaults to headless [OK]

Hint: Verify --headed flag spelling and presence when headed mode fails [OK]

Common Mistakes:

• Confusing --headed with --headless
• Assuming Cypress doesn't support headed Chrome
• Ignoring browser installation status

5. You want to run tests only in Firefox, headlessly, and save the results to a JSON file named results.json. Which command achieves this?

hard

A. cypress open --browser firefox --headless --output results.json

B. cypress run --browser firefox --headed --reporter json --output results.json

C. cypress run --browser firefox --headless --reporter json --reporter-options output=results.json

D. cypress run --browser firefox --headless --output results.json

Solution

1. Step 1: Choose correct command and browser

   Use cypress run to run tests headlessly and specify --browser firefox.

2. Step 2: Specify headless mode and JSON reporter output

   Use --headless for no UI, --reporter json to format output, and --reporter-options output=results.json to save results.

3. Final Answer:

   cypress run --browser firefox --headless --reporter json --reporter-options output=results.json -> Option C

4. Quick Check:

   Use reporter options to save JSON results [OK]

Hint: Use --reporter and --reporter-options to save JSON output [OK]

Common Mistakes:

• Using 'cypress open' instead of 'cypress run'
• Missing --reporter or reporter-options flags
• Confusing --headed with --headless