#Testing

How to Use Vitest with Zowl

Generate and run Vitest tests overnight — fast, native ESM, zero config.

What is Vitest?

Vitest is a blazing fast unit test framework powered by Vite. It supports ESM natively, has Jest-compatible APIs, and runs tests significantly faster than alternatives. Zowl integrates Vitest as a pipeline step so agents can generate tests, execute them, and enforce coverage — all overnight.

How Zowl Helps

Zowl orchestrates the full test lifecycle: agents write Vitest tests, Zowl runs them with coverage tracking, and failed tests get retried with error context. Coverage thresholds ensure agents keep improving until your bar is met.

Setup Guide

01

Ensure Vitest is Installed

Your project needs Vitest configured. Zowl runs Vitest via CLI, so npx vitest should work in your repo.

02

Add Test Execution Step

In your pipeline, add a 'Run Tests' node that executes npx vitest run after agent code generation.

03

Set Coverage Thresholds

Configure minimum coverage percentages. Agents retry if their tests don't meet your threshold.

04

Enable Watch Mode for Dev

Use Vitest's watch mode during development for rapid agent-test iteration.

Capabilities

Fast Execution

Vitest runs 2-5x faster than Jest in most projects — meaning more test iterations per overnight run.

ESM Native

No CJS/ESM compatibility issues. Vitest understands modern JavaScript natively.

Coverage Gating

Set coverage thresholds. If tests don't meet the bar, the agent gets another attempt with the coverage report.

Jest-Compatible API

Agents that know Jest can write Vitest tests — same describe/it/expect API.

Frequently Asked Questions

Either works. Vitest is faster and better for ESM projects. Jest has a larger ecosystem. Zowl doesn't care — it runs whatever CLI command you configure.

Yes. Agents can use Vitest-specific features like in-source testing, concurrent tests, and benchmark mode when configured.

Yes. Vitest uses c8 or istanbul for coverage. Output formats (text, lcov, html) are all supported and captured by Zowl.

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