Interface ExtensionTester<UOutput>

interface ExtensionTester<UOutput extends ExtensionDataRef> {
    add<T extends ExtensionDefinitionParameters>(
        extension: ExtensionDefinition<T>,
        options?: { config?: T["configInput"] },
    ): ExtensionTester<UOutput>;
    get<TId extends string>(
        ref: ExtensionDataRef<any, TId, any>,
    ): UOutput extends ExtensionDataRef<IData, TId, IConfig>
        ? IConfig["optional"] extends true ? IData | undefined : IData
        : never;
    query<T extends ExtensionDefinitionParameters>(
        extension: ExtensionDefinition<T>,
    ): ExtensionQuery<NonNullable<T["output"]>>;
    reactElement(): Element;
}