karma

Executes JavaScript tests in actual browsers like Chrome and Firefox, ensuring accurate cross-browser compatibility by launching an HTTP server and generating test runner HTML files, as highlighted in the README.

Runs tests simultaneously across multiple desktop and mobile browsers, providing comprehensive coverage for web applications without relying on simulated environments.

Configurable to automatically run tests on every file save during development, facilitating fast feedback loops for test-driven development, as mentioned in the key features.

Works with popular testing frameworks such as Jasmine, Mocha, and QUnit via plugins, allowing developers to use their preferred tools without lock-in, as noted in the philosophy section.

Supports Istanbul for automatically generating code coverage reports, helping teams track testing completeness, which is a listed feature in the README.