def "registers LanguageSourceSet"() {
        when:
        dsl {
            apply plugin: LanguageBasePlugin
            model {
                baseSourceSet(LanguageSourceSet) {
                }
            }
        }

        then:
        realize("baseSourceSet") instanceof LanguageSourceSet
    }

    def "adds a 'sources' container to the project model"() {
        when:
        dsl {