From the community: Front-end testing and feature flags

Ioannis Papadopoulos discusses strategies for integrating feature flags into automated front-end testing, emphasizing the importance of writing tests that mirror real-world software usage and focusing on test logic over setup. At Harbr, a platform that facilitates data commerce, they use TypeScript, React, Jest, Storybook, and Unleash to manage feature flags, which are crucial for controlling feature deployment due to the diverse technical environments and commercial needs of their customers. To enhance testing efficiency and maintain seamless developer experience, Harbr employs a custom FeatureFlagProvider to wrap tests and stories, using msw.js to mock API requests and simulate different feature flag states. This setup allows for zero-configuration integration tests, even when feature flags are indirectly used, and supports visual regression testing in Storybook. Papadopoulos advises against testing implementation details and recommends using globally available defaults with the flexibility to override them for specific component tests.