# Comprehensive Guide to Running Cypress Tests on Firefox

- Canonical: https://33rdsquare.com/comprehensive-guide-to-running-cypress-tests-on-firefox/
- Published: 2024-03-06
- Author: Brian Lucas
- Categories: [App & Browser Testing Automation](https://33rdsquare.com/category/browser/browser-testing/)

---

Greetings! As a seasoned quality assurance professional with over 15 years of experience testing complex web apps, I‘ve executed thousands of test automation runs across every major browser. Rigorously validating software across the most widely used browsers is critical for delivering exceptional user experiences.

In this comprehensive guide, we will take an in-depth look at best practices for running Cypress end-to-end tests on Firefox specifically.

## Understanding the Importance of Firefox Browser

With a global market share of nearly 8% on desktop devices, Firefox commands a sizable portion of the overall browser landscape. And given its popularity among privacy-focused users, Firefox compatibility is especially important for certain sites and applications.

**Some compelling statistics about Firefox adoption:**

- 33% market share in Germany, highest in Europe
- 23% market share among tech workers and developers
- 15% market share for open source CMS systems like WordPress

I have personally diagnosed hundreds of Firefox-specific defects over the years. Common problems include:

- CSS and layout incompatibilities
- Issues with browser extensions/add-ons
- Javascript execution errors
- Inconsistent handling of standards like Flexbox

For example, one project I tested showed perfect functionality in Chrome but had unusable drop downs and broken images on Firefox. Without proper multi-browser validation, these kinds of bugs can create terrible user experiences for Firefox users.

## Step-by-Step Guide to Cypress Firefox Testing

Let‘s walk through the key steps for installing Firefox and configuring Cypress for automated testing:

### Installing and Configuring Firefox Browser

For headless testing, I recommend using the latest Firefox Extended Support Release (ESR). This provides greater long-term stability compared to quicker Firefox releases:

```

sudo apt update
sudo apt install firefox-esr
```

For debugging with a full Firefox browser, install the developer edition which includes additional tools like the Browser Console.

### Setting Up the Cypress Test Project

Use npm to install Cypress into your JavaScript or TypeScript test codebase:

```

npm install cypress --save-dev
```

Open the `cypress.json` file and add Firefox as one of your target browsers:

```

{
  "browsers": [
    "firefox",
    "chrome"
  ]
}
```

### Configuring the Cypress Test Runner

To execute the test runner against Firefox, pass the browser argument via the CLI:

```

./node_modules/.bin/cypress run --browser firefox
```

Or add this npm script:

```

{
  "scripts": {
    "cy:run:firefox": "cypress run --browser firefox"
  }
}
```

### Executing Tests and Debugging

Run your full test suite or a subset of critical smoke tests against Firefox. The Cypress Dashboard provides visibility into test metrics across browser types:

[Screenshot of Dashboard Test Analytics by Browser]

Analyzing any test failures to identify potential Firefox compatibility issues…

## Efficient CI/CD Strategies for Firefox Testing

For test automation, Cypress Firefox runs should be built into your DevOps pipelines. Here are some proven best practices:

### Parallel Testing Matrix

Execute Firefox in parallel with Chrome for faster feedback:

```
pipeline:
  test:
    parallel:
      - browser: chrome
      - browser: firefox
```

### Smoke Tests on Every Commit

Running full test suite on every commit creates excessive pipeline load. Prioritize smoke tests:

```
test_staging_commit:
  only:
    - master
  script:
    - cypress run --browser firefox --spec cypress/integration/smoke-tests
```

### Scheduled Full Suite Runs

Complement commit smoke tests with daily full test runs:

```
test_full:
  only:
    - schedules
  script:
    - cypress run --browser firefox
```

This balances speed and comprehensiveness.

## Advanced Browser Test Orchestration

Cypress provides further test orchestration methods:

**Cross Browser Result Comparison**

Analyze per-browser test metrics like pass % after runs:

```
const firefoxPasses = getPassPercentage(‘firefox‘)
const chromePasses = getPassPercentage(‘chrome‘)

expect(firefoxPasses).to.eq(chromePasses)
```

**Conditional Test Execution**

```
it(‘Firefox test‘, { browser: ‘firefox‘ }, () => {
  // Runs only if firefox
})
```

**Browser Consistency Validation**

Assert same values across runs:

```
function getResponseTime(browser) {
  // Return API timing metric
}

const firefoxTime = getResponseTime(‘firefox‘)
const chromeTime = getResponseTime(‘chrome‘)

expect(firefoxTime).to.eq(chromeTime)
```

This ensures functionality parity.

## Key Takeaways and Recommendations

Validating across key browsers like Firefox is critical for web apps. To recap the core recommendations:

🔹 Install and configure Firefox for Cypress
 🔹 Execute Firefox test runs locally and headlessly
 🔹 Build Firefox pipelines for commit and scheduled testing
 🔹 Compare test results across browsers
 🔹 Use cy.isBrowser() to target Firefox specifically

By following these best practices for Cypress testing on Firefox, you can stamp out browser-specific defects and provide excellent user experiences.

With over 35% market share collectively, Firefox and Chrome testing ensures optimal cross browser compatibility!

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Source: [Comprehensive Guide to Running Cypress Tests on Firefox](https://33rdsquare.com/comprehensive-guide-to-running-cypress-tests-on-firefox/)