This blog post by Andrey Shevchenko provides an overview on how to write functional tests for Groovy using Geb and Spock technologies with a detailed example. Geb is a browser automation solution that brings together the power of WebDriver, the elegance of jQuery content selection, the robustness of Page Object modelling and the expressiveness of the Groovy language.
Spock is a testing and specification framework for Java and Groovy applications. What makes it stand out from the crowd is its beautiful and highly expressive specification language. Thanks to its JUnit runner, Spock is compatible with most IDEs, build tools, and continuous integration servers.