Exclude from production.

excludes.groovy

if(System.getProperty('grails.env') == 'test') {
    test(':spock:0.7') {
      excludes 'spock-grails-support', 'hibernate', 'grails-hibernate'
    }
    test ':code-coverage:1.2.5'
}

One downside to this approach is that Grails caches its dependencies (see the .resolve file in the working directory). So switching between environments may introduce subtle problems unless you force a dependency refresh each time.

My preferred approach is to add an eventCreateWarStart handler to the build that strips out the test dependencies before packaging the WAR. It's also pretty hacky 😄