export declare function assertRejects(promise: Promise<any>, expectedError?: string | RegExp | typeof Error): Promise<void>;
export interface TestFixture<T> {
    setup: () => T | Promise<T>;
    teardown?: (fixture: T) => void | Promise<void>;
}
export declare function withFixture<T, R>(fixture: TestFixture<T>, fn: (fixture: T) => R | Promise<R>): Promise<R>;