/**
 * @author Martin Karkowski
 * @email m.karkowski@zema.de
 */
/**
 * Delays some execution. Sleeps the amount of time in **ms**
 * @param delay [ms]
 * @returns void
 */
export declare function sleep(delay: number): Promise<void>;
/**
 * Tests if a Function is async or not.
 * @param func The function to test.
 * @returns {boolean} The test result.
 */
export declare function isAsyncFunction(func: (...args: any[]) => any): boolean;
/**
 * Function which will halt the Process until the Testcallback deliveres "true"
 *
 * @export
 * @param {(() => boolean | Promise<boolean>)} testCallback Function which is used to periodically test the State
 * @param {{ testFirst?: boolean; maxRetries?: number, timeout?: number, maxTimeout?: number }} [options={}] Options to enhance the behavior. Look at the details
 * @returns
 */
export declare function waitFor(testCallback: () => boolean | Promise<boolean>, options?: {
    /**
     * Inital delay, before the test is started.
     */
    initialWait?: number;
    /**
     * Flag to enable testing the call the callback directly before
     * proceeding or just ensure the inital waiting time
     */
    testFirst?: boolean;
    /**
     * Max amount of retries before an execption is raised
     */
    maxRetries?: number;
    /**
     * Delay to wait, after an unsucessfull test.
     */
    delay?: number;
    /**
     * Timeout afterwhich the Test will fail.
     */
    maxTimeout?: number;
    /**
     * A Delay which is added after the Test is fullfilled,
     * before the Promise is done.
     */
    additionalDelay?: number;
}): Promise<void>;