The Grails docs
talk about testing and have some example test methods but fail to describe some
simple but necessary mechanics to get it going. The test methods should be in
a class that extends GroovyTestCase (that word doesn't appear at all when
searching the Grails website). The class name must end with Tests since it
must be in a file with a name ending in Tests.groovy under the test
directory of your grails project.