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

Property based testing framework for JavaScript (like QuickCheck)

import type { Random } from '../../random/generator/Random.js';
import type { Stream } from '../../stream/Stream.js';
import type { Value } from '../arbitrary/definition/Value.js';
import type { PreconditionFailure } from '../precondition/PreconditionFailure.js';
/**
 * Represent failures of the property
 * @remarks Since 3.0.0
 * @public
 */
export type PropertyFailure = {
    /**
     * The original error that has been intercepted.
     * Possibly not an instance Error as users can throw anything.
     * @remarks Since 3.0.0
     */
    error: unknown;
    /**
     * The error message extracted from the error
     * @remarks Since 3.0.0
     */
    errorMessage: string;
};
/**
 * Property
 *
 * A property is the combination of:
 * - Arbitraries: how to generate the inputs for the algorithm
 * - Predicate: how to confirm the algorithm succeeded?
 *
 * @remarks Since 1.19.0
 * @public
 */
export interface IRawProperty<Ts, IsAsync extends boolean = boolean> {
    /**
     * Is the property asynchronous?
     *
     * true in case of asynchronous property, false otherwise
     * @remarks Since 0.0.7
     */
    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
     *
     * @remarks Since 0.0.7 (return type changed in 3.0.0)
     */
    generate(mrng: Random, runId?: number): Value<Ts>;
    /**
     * Shrink value of type Ts
     *
     * @param value - The value to be shrunk, it can be context-less
     *
     * @remarks Since 3.0.0
     */
    shrink(value: Value<Ts>): Stream<Value<Ts>>;
    /**
     * Check the predicate for v
     * @param v - Value of which we want to check the predicate
     * @param dontRunHook - Do not run beforeEach and afterEach hooks within run
     * @remarks Since 0.0.7
     */
    run(v: Ts, dontRunHook?: boolean): (IsAsync extends true ? Promise<PreconditionFailure | PropertyFailure | null> : never) | (IsAsync extends false ? PreconditionFailure | PropertyFailure | null : never);
    /**
     * Run before each hook
     * @remarks Since 3.4.0
     */
    runBeforeEach?: () => (IsAsync extends true ? Promise<void> : never) | (IsAsync extends false ? void : never);
    /**
     * Run after each hook
     * @remarks Since 3.4.0
     */
    runAfterEach?: () => (IsAsync extends true ? Promise<void> : never) | (IsAsync extends false ? void : never);
}