thrown UnknownDomainObjectException
    }

    def "configure extension"() {
        when:
        def shouldNotExist = "shouldNotExist"
        storage.configureExtension(shouldNotExist, {})
        then:
        def t = thrown UnknownDomainObjectException
        t.message.startsWith("Extension with name '$shouldNotExist' does not exist.")
    }

    def "find extension"() {
        when: