fast-check/lib/types/check/runner/configuration/Parameters.d.ts

Property based testing framework for JavaScript (like QuickCheck)

import { RandomGenerator } from 'pure-rand';
import { RandomType } from './RandomType';
import { VerbosityLevel } from './VerbosityLevel';
import { RunDetails } from '../reporter/RunDetails';
/**
 * Customization of the parameters used to run the properties
 */
export interface Parameters<T = void> {
    /**
     * Initial seed of the generator: `Date.now()` by default
     *
     * It can be forced to replay a failed run.
     *
     * In theory, seeds are supposed to be 32 bits integers.
     * In case of double value, the seed will be rescaled into a valid 32 bits integer (eg.: values between 0 and 1 will be evenly spread into the range of possible seeds).
     */
    seed?: number;
    /**
     * Random number generator: `xorshift128plus` by default
     *
     * Random generator is the core element behind the generation of random values - changing it might directly impact the quality and performances of the generation of random values.
     * It can be one of: 'mersenne', 'congruential', 'congruential32', 'xorshift128plus', 'xoroshiro128plus'
     * Or any function able to build a `RandomGenerator` based on a seed
     */
    randomType?: RandomType | ((seed: number) => RandomGenerator);
    /**
     * Number of runs before success: 100 by default
     */
    numRuns?: number;
    /**
     * Maximal number of skipped values per run
     *
     * Skipped is considered globally, so this value is used to compute maxSkips = maxSkipsPerRun * numRuns.
     * Runner will consider a run to have failed if it skipped maxSkips+1 times before having generated numRuns valid entries.
     *
     * See {@link pre} for more details on pre-conditions
     */
    maxSkipsPerRun?: number;
    /**
     * Maximum time in milliseconds for the predicate to answer: disabled by default
     *
     * WARNING: Only works for async code (see {@link asyncProperty}), will not interrupt a synchronous code.
     */
    timeout?: number;
    /**
     * Skip all runs after a given time limit: disabled by default
     *
     * NOTE: Relies on `Date.now()`.
     *
     * NOTE:
     * Useful to stop too long shrinking processes.
     * Replay capability (see {@link seed}, {@link path}) can resume the shrinking.
     *
     * WARNING:
     * It skips runs. Thus test might be marked as failed.
     * Indeed, it might not reached the requested number of successful runs.
     */
    skipAllAfterTimeLimit?: number;
    /**
     * Interrupt test execution after a given time limit: disabled by default
     *
     * NOTE: Relies on `Date.now()`.
     *
     * NOTE:
     * Useful to avoid having too long running processes in your CI.
     * Replay capability (see {@link seed}, {@link path}) can still be used if needed.
     *
     * WARNING:
     * If the test got interrupted before any failure occured
     * and before it reached the requested number of runs specified by {@link numRuns}
     * it will be marked as success. Except if {@link markInterruptAsFailure} as been set to `true`
     */
    interruptAfterTimeLimit?: number;
    /**
     * Mark interrupted runs as failed runs: disabled by default
     */
    markInterruptAsFailure?: boolean;
    /**
     * Way to replay a failing property directly with the counterexample.
     * It can be fed with the counterexamplePath returned by the failing test (requires `seed` too).
     */
    path?: string;
    /**
     * Logger (see {@link statistics}): `console.log` by default
     */
    logger?(v: string): void;
    /**
     * Force the use of unbiased arbitraries: biased by default
     */
    unbiased?: boolean;
    /**
     * Enable verbose mode: {@link VerbosityLevel.None} by default
     *
     * Using `verbose: true` is equivalent to `verbose: VerbosityLevel.Verbose`
     *
     * It can prove very useful to troubleshoot issues.
     * See {@link VerbosityLevel} for more details on each level.
     */
    verbose?: boolean | VerbosityLevel;
    /**
     * Custom values added at the beginning of generated ones
     *
     * It enables users to come with examples they want to test at every run
     */
    examples?: T[];
    /**
     * Stop run on failure
     *
     * It makes the run stop at the first encountered failure without shrinking.
     *
     * When used in complement to `seed` and `path`,
     * it replays only the minimal counterexample.
     */
    endOnFailure?: boolean;
    /**
     * Replace the default reporter handling errors by a custom one
     *
     * Reporter is responsible to throw in case of failure: default one throws whenever `runDetails.failed` is true.
     * But you may want to change this behaviour in yours.
     *
     * Only used when calling `fc.assert`
     * Cannot be defined in conjonction with `asyncReporter`
     */
    reporter?: (runDetails: RunDetails<T>) => void;
    /**
     * Replace the default reporter handling errors by a custom one
     *
     * Reporter is responsible to throw in case of failure: default one throws whenever `runDetails.failed` is true.
     * But you may want to change this behaviour in yours.
     *
     * Only used when calling `fc.assert`
     * Cannot be defined in conjonction with `reporter`
     * Not compatible with synchronous properties: runner will throw
     */
    asyncReporter?: (runDetails: RunDetails<T>) => Promise<void>;
}