Testing Feature Flags and Toggles in Playwright

In modern web development, feature flags (also known as feature toggles) play a vital role in deploying new functionality safely and incrementally. They allow developers to roll out features gradually, perform A/B testing, or even disable risky code without redeploying the application. While feature flags offer flexibility, they also introduce complexity in testing.

With the rise of powerful end-to-end testing tools like Playwright, it's now easier than ever to automate tests that validate feature flag behavior across different user scenarios. In this blog, we'll explore how to test feature flags using Playwright effectively.


🎯 What Are Feature Flags?

Feature flags are conditional statements that enable or disable functionality based on configuration. They are typically managed using flag management systems like:

LaunchDarkly

Unleash

Firebase Remote Config

Split.io

Custom environment-based toggles

Flags can be turned on/off per user, environment, group, or device. For example:


javascript


if (isFeatureEnabled('new-dashboard')) {

  renderNewDashboard();

} else {

  renderOldDashboard();

}


🧪 Why Test Feature Flags?

Prevent regressions: Ensure both enabled and disabled states work as expected.

Test rollouts: Validate partial feature releases for specific users or environments.

Avoid dead flags: Ensure old toggles don’t impact current features.

Skipping tests for flags may result in broken UI/UX when toggles are flipped in production.


🔧 Testing Feature Flags in Playwright

Playwright’s flexibility makes it perfect for simulating different flag conditions. Here’s how:

1. Mocking Feature Flags (Intercepting Network Calls)

If flags are fetched from an API, Playwright allows you to intercept and mock the response.

ts


await page.route('**/feature-flags', async route => {

  route.fulfill({

    status: 200,

    body: JSON.stringify({

      newDashboard: true,

      betaFeature: false

    }),

    contentType: 'application/json'

  });

});

This lets you simulate any flag configuration without modifying the backend or deployment settings.


2. Testing Both On/Off States

Create separate test scenarios for each flag state:


ts


test('New dashboard is shown when flag is enabled', async ({ page }) => {

  await mockFeatureFlags(page, { newDashboard: true });

  await page.goto('/dashboard');

  await expect(page.locator('h1')).toHaveText('New Dashboard');

});


test('Old dashboard is shown when flag is disabled', async ({ page }) => {

  await mockFeatureFlags(page, { newDashboard: false });

  await page.goto('/dashboard');

  await expect(page.locator('h1')).toHaveText('Old Dashboard');

});

This ensures your code behaves correctly regardless of the toggle’s state.


3. Parametrize with Test Fixtures

Create reusable test fixtures in Playwright to test with different user roles or flag conditions.


ts

Copy

Edit

test.describe('Dashboard feature flag', () => {

  const flags = [true, false];


  for (const flag of flags) {

    test(`should render correct dashboard (flag=${flag})`, async ({ page }) => {

      await mockFeatureFlags(page, { newDashboard: flag });

      await page.goto('/dashboard');

      // Add assertions

    });

  }

});


✅ Best Practices

Automate both flag states to ensure full coverage

Clean up mocks to avoid interference between tests

Use CI environments with known flag setups

Regularly audit flags and remove deprecated toggles


📌 Conclusion

Feature flags are a powerful tool for releasing software safely, but they also introduce branching logic that needs to be tested thoroughly. With Playwright, you can easily simulate flag conditions, validate UI variations, and ensure feature toggles don’t lead to unexpected behaviors. By treating feature flags as first-class citizens in your test strategy, you’ll maintain product quality and ship new features with confidence


Learn Playwright Testing Training

Read More: Secure Login Flows for Enterprise Apps in Playwright

Read More: Automating A/B Testing Scenarios with Playwright

Read More :Combining Test IDs with Data Attributes in Playwright

Visit IHUB Talent Institute Hyderabad

Get Direction

Comments

Post a Comment

Popular posts from this blog

How to Use Tosca's Test Configuration Parameters

Tosca by Tricentis is a powerful model-based test automation tool widely used in enterprise environments for end-to-end testing. One of its most useful features is Test Configuration Parameters (TCPs), which provide flexibility and control in managing test execution. TCPs enable testers to create reusable test cases by passing dynamic values without hardcoding them. This significantly enhances test maintenance, scalability, and efficiency. In this blog, we’ll explore what Test Configuration Parameters are, how to create and use them, and the best practices to follow when working with TCPs in Tosca. What Are Test Configuration Parameters? Test Configuration Parameters are custom-defined key-value pairs that can be associated with test cases, test case folders, or execution lists in Tosca. They help manage configuration data such as environment URLs, browser types, credentials, or any other variable data that may differ across test runs. By using TCPs, you can avoid duplicating test case...
Read more

Using Hibernate ORM for Fullstack Java Data Management

In the world of fullstack Java development, managing data efficiently and seamlessly across the application is critical. One of the most powerful tools in the Java ecosystem for handling database operations is Hibernate ORM (Object-Relational Mapping). Hibernate simplifies the interaction between Java applications and relational databases, reducing boilerplate code and improving maintainability. This blog explores how Hibernate ORM works, why it’s widely used, and how it fits into the data management strategy of a fullstack Java application. What is Hibernate ORM? Hibernate ORM is an open-source Java framework that provides a powerful and flexible mechanism for mapping Java objects to database tables. It abstracts the low-level JDBC code, allowing developers to work with high-level object-oriented concepts. Instead of writing raw SQL queries, Hibernate allows developers to define database interactions using simple Java classes (also known as POJOs) and annotations or XML configurations...
Read more

Creating a Test Execution Report with Charts in Playwright

Modern test automation isn't just about running tests—it's also about presenting clear, visual feedback on test results. When working with Playwright, one of the most powerful end-to-end testing tools for modern web apps, generating detailed execution reports can help your team track progress, identify issues quickly, and make data-driven decisions. A visual report with charts brings your testing efforts to life. In this blog, we’ll walk through how to create a test execution report with charts using Playwright’s built-in capabilities along with third-party tools for enhanced visualization. Why Visual Reports Matter Plain text logs and console outputs are hard to parse at scale. A good report should answer questions like: How many tests passed or failed? What’s the overall success rate? Which tests are flaky or slow? How have test results changed over time? Visualizing this data with charts—like pie charts, bar graphs, or timelines—helps QA teams and stakeholders better underst...
Read more