* <p>
     * This applies to the standard {@link java.util.Collection} methods such as {@code add()}, {@code remove()}
     * and {@code clear()}.
     */
    class ImmutableViolationException extends GradleException {
        public ImmutableViolationException() {
            super("ReportContainer objects are immutable");
        }
    }

    /**

    def "container is immutable"() {
        when:
        container.add(Stub(Report))

        then:
        thrown(ReportContainer.ImmutableViolationException)

        when:
        container.clear()

        then:
        thrown(ReportContainer.ImmutableViolationException)
    }

    def "require empty by default"() {
        expect:
        container.every { !it.required.get() } && container.enabled.empty

                return element.getRequired().get();
            }
        });
    }

    @Override
    protected void assertMutableCollectionContents() {
        throw new ImmutableViolationException();
    }

    @Override
    public NamedDomainObjectSet<T> getEnabled() {
        return enabled;
    }

    @Override
    public ReportContainer<T> configure(Closure cl) {