vitest 5.x

Use Vitest ^5.0.0 standalone assertions and mock functions correctly, while avoiding APIs that require the Vitest runner and accounting for v5 migration changes.

For

vitest@5.0.0

Verified

2026-09-07, 5 examples executed

Package

@modootoday/pmcp-vitest@5.0.0

What it covers

• Requirements
• What can run in a plain script
• Assertions
• Mock functions
• Spying on an object method
• Conditional mock behavior with `vi.when`
• Mock lifecycle APIs
• APIs that require the Vitest runner
• v5 benchmarks
• Module mocking
• v5 migration traps
• Not covered

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 { expect } from 'vitest'

expect(Math.sqrt(4)).toBe(2)
expect(Math.sqrt(144)).toBe(12)
expect(Math.sqrt(0)).toBe(0)
expect(0.1 + 0.2).toBeCloseTo(0.3)
expect('vitest').toContain('test')

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-vitest

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