fast-check/lib/esm/check/property/Property.generic.js

Property based testing framework for JavaScript (like QuickCheck)

import { PreconditionFailure } from '../precondition/PreconditionFailure.js';
import { runIdToFrequency } from './IRawProperty.js';
export class Property {
    constructor(arb, predicate) {
        this.arb = arb;
        this.predicate = predicate;
        this.beforeEachHook = Property.dummyHook;
        this.afterEachHook = Property.dummyHook;
        this.isAsync = () => false;
    }
    generate(mrng, runId) {
        return runId != null ? this.arb.withBias(runIdToFrequency(runId)).generate(mrng) : this.arb.generate(mrng);
    }
    run(v) {
        this.beforeEachHook();
        try {
            const output = this.predicate(v);
            return output == null || output === true ? null : 'Property failed by returning false';
        }
        catch (err) {
            if (PreconditionFailure.isFailure(err))
                return err;
            if (err instanceof Error && err.stack)
                return `${err}\n\nStack trace: ${err.stack}`;
            return `${err}`;
        }
        finally {
            this.afterEachHook();
        }
    }
    beforeEach(hookFunction) {
        this.beforeEachHook = hookFunction;
        return this;
    }
    afterEach(hookFunction) {
        this.afterEachHook = hookFunction;
        return this;
    }
}
Property.dummyHook = () => { };