registry.get(StringBuilder.class)

        then:
        UnknownServiceException e = thrown()
        e.message == "No service of type StringBuilder available in TestRegistry."
    }

    def delegatesToParentForUnknownService() {
        def value = BigDecimal.TEN
        def parent = Mock(ParentServices)
        def registry = new TestRegistry(registry(parent))

        when:
        def result = registry.get(BigDecimal)