e.message == "ProjectDescriptor with ID 'desc1' already registered."
    }

    def "getAllTypes lists all registered types"() {
        setup:
        registry.add(generator("desc1"))
        registry.add(generator("desc2"))
        registry.add(generator("desc3"))

        expect:
        registry.getAllTypes() == ["default", "desc1", "desc2", "desc3", "maven"]
    }

    def "lookup fails for unknown type"() {

            formatter.node("The requested build type '" + type + "' is not supported. Supported types");
            formatter.startChildren();
            for (String candidate : getAllTypes()) {
                formatter.node("'" + candidate + "'");
            }
            formatter.endChildren();
            throw new GradleException(formatter.toString());
        }

    public void setType(String type) {
        this.type = type;
    }

    @OptionValues("type")
    public List<String> getAvailableBuildTypes() {
        return getProjectLayoutRegistry().getAllTypes();
    }

    /**
     * Set the build script DSL to be used.
     *
     * @since 4.5
     */
    @Option(option = "dsl", description = "Set the build script DSL to be used in generated scripts.")