return matcher.matches(string.replace(SystemProperties.getInstance().getLineSeparator(), "\n"));
            }

            @Override
            public void describeTo(Description description) {
                matcher.describeTo(description);
                description.appendText(" (normalize line separators)");
            }
        };
    }

        this.parent = parent;
        this.child = child;
    }

    @Override
    public void describeTo(Appendable appendable) {
        parent.describeTo(appendable);
        try {
            appendable.append(" > ");
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
        child.describeTo(appendable);
    }

    @Override
    public boolean equals(Object o) {

        descriptor.describeTo(builder);
        return builder.toString();
    }

    private static String toMessage(ModelRuleDescriptor descriptor, String error) {
        StringBuilder builder = new StringBuilder("error executing model rule: ");
        descriptor.describeTo(builder);
        builder.append(" - ");
        builder.append(error);

class MethodModelRuleDescriptorTest extends Specification {

    def "check description"() {
        when:
        def sb = new StringBuilder()
        MethodModelRuleDescriptor.of(weakMethod(getClass(), method)).describeTo(sb)

        then:
        sb.toString() == ModelType.of(getClass()).displayName + "#" + desc

        where:
        method        | desc
        "noArgs"      | 'noArgs()'

 */
public interface ModelRuleDescriptor {
    /**
     * This method is expected to be idempotent.
     *
     * @param appendable where to write the description to.
     */
    void describeTo(Appendable appendable);

    ModelRuleDescriptor append(ModelRuleDescriptor child);

    ModelRuleDescriptor append(String child);

    @FormatMethod

    public RejectedVersion(ModuleComponentIdentifier id) {
        this.id = id;
    }

    public ModuleComponentIdentifier getId() {
        return id;
    }

    public void describeTo(TreeFormatter builder) {
        builder.node(id.getVersion());
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }

            result.append(" of type '");
            result.append(type.getDisplayName());
            result.append("'");
        }
        result.append(" given to rule ");
        ruleDescriptor.describeTo(result);
        return result.toString();
    }

            result.append(" of type '");
            result.append(type.getDisplayName());
            result.append("'");
        }
        result.append(" given to rule ");
        ruleDescriptor.describeTo(result);
        return result.toString();
    }

    public UserAgentMatcher(String applicationName, String version) {
        this.applicationName = applicationName;
        this.version = version;
    }

    @Override
    public void describeTo(Description description) {
        description.appendValue(expectedUserAgentString());
    }

    @Factory
    public static UserAgentMatcher matchesNameAndVersion(String applicationName, String version) {

        return append(String.format(child, args));
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        describeTo(sb);
        return sb.toString();
    }