Cypress CLI execution

Introduction

Cypress CLI lets you run your tests from the command line. This helps you test your app automatically without opening the browser UI.

You want to run tests on a server or in a continuous integration system.

You want to run all tests quickly without manual clicks.

You want to see test results in the terminal or save reports.

You want to run tests in different browsers or headless mode.

You want to automate testing as part of your development workflow.

Syntax

Cypress

npx cypress run [options]

npx cypress run runs all tests in headless mode by default.

You can add options like --browser chrome or --spec 'cypress/e2e/test.cy.js' to customize the run.

Examples

Runs all tests in the default browser (usually Electron) in headless mode.

Cypress

npx cypress run

Runs all tests in Google Chrome browser in headless mode.

Cypress

npx cypress run --browser chrome

Runs only the test file named login.cy.js.

Cypress

npx cypress run --spec 'cypress/e2e/login.cy.js'

Runs tests in Firefox browser with the browser window visible (not headless).

Cypress

npx cypress run --headed --browser firefox

Sample Program

This command runs the sample_test.cy.js test file using Chrome browser in headless mode. You will see test results in the terminal.

Cypress

npx cypress run --spec 'cypress/e2e/sample_test.cy.js' --browser chrome

Important Notes

Use npx to run Cypress without installing it globally.

Headless mode means tests run without opening the browser window.

You can save test videos and screenshots automatically with Cypress CLI.

Summary

Cypress CLI runs tests from the command line without the UI.

You can choose browser, test files, and headless or headed mode with options.

Test results show in the terminal, useful for automation and continuous integration.

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