# Verifier

Unit testing using js-test-driver and BDD-style acceptance tests integrated with BladeRunner

![Verifier_v2-component-screenshot](../../../images/Verifier_v2-component-screenshot.png)

## Features

### Descriptive Given-When-Then tests

Specify your [blade’s](../bladerunner/bladerunner-application-structure.md#blades) required behaviour in easy-to-read tests, write [fixtures](verifier-available-fixtures.md) to exercise it and verifier runs the test.

### Modular tests

Keep component tests short and modular by running sequences of tests, with each test following on from the state reached by the previous one.

### Unit testing using Google’s js-test-driver

Blazingly fast tests only load the code once per run rather than per-test. Runs tests in multiple browsers simultaneously.

### Integrated with BladeRunner

BladeRunner’s [bundlers](../bladerunner/bladerunner-about-bundlers.md) work out what JavaScript, HTML and CSS to load. Verifier locates your tests and runs them.