fast-check 4.x

Use fast-check 4.x for property-based testing in standalone JavaScript/TypeScript scripts, with v3-to-v4 migration guidance and runnable Bun examples.

For

fast-check@4.9.0

Verified

2026-09-08, 7 examples executed

Package

@modootoday/pmcp-fast-check@4.0.0

What it covers

• Runtime and language requirements
• Properties, preconditions, and assertions
• Inspecting runs with `check`
• Sampling arbitraries
• Global configuration
• Common arbitraries and v4 inference
• v3-to-v4 migration traps
• What this skill does not cover

One example from this skill

This is the skill's own text, not a summary of it. It runs: that is what verifying means here.

import * as fc from 'fast-check';
import assert from 'node:assert/strict';

const values = fc.sample(fc.nat(), 10);
assert.equal(values.length, 10);
assert.ok(values.every((value) => Number.isInteger(value) && value >= 0));

What it did in the sandbox

Verifying this skill meant installing the package and running code against it with no route out. Nothing was observed. The full ledger lists every package examined, including the ones that never became a skill.

Nothing observed is not a finding of safety. It means one run, under one policy, produced nothing to report.

Getting it

With a subscription:

npx -y @modootoday/pmcp login
npx -y @modootoday/pmcp install @modootoday/pmcp-fast-check

It installs as a dev dependency of your project, and the MCP server finds it there like any other skill.