fast-check/lib/types/check/property/IRawProperty.d.ts

Property based testing framework for JavaScript (like QuickCheck)

import { Random } from '../../random/generator/Random';
import { Shrinkable } from '../arbitrary/definition/Shrinkable';
import { PreconditionFailure } from '../precondition/PreconditionFailure';
/**
 * Property
 *
 * A property is the combination of:
 * - Arbitraries: how to generate the inputs for the algorithm
 * - Predicate: how to confirm the algorithm succeeded?
 */
export interface IRawProperty<Ts, IsAsync extends boolean = boolean> {
    /**
     * Is the property asynchronous?
     *
     * true in case of asynchronous property, false otherwise
     */
    isAsync(): IsAsync;
    /**
     * Generate values of type Ts
     *
     * @param mrng - Random number generator
     * @param runId - Id of the generation, starting at 0 - if set the generation might be biased
     */
    generate(mrng: Random, runId?: number): Shrinkable<Ts>;
    /**
     * Check the predicate for v
     * @param v - Value of which we want to check the predicate
     */
    run(v: Ts): (IsAsync extends true ? Promise<PreconditionFailure | string | null> : never) | (IsAsync extends false ? PreconditionFailure | string | null : never);
}