Quick Start

Write a first test file, add a config, and run the test suite.

This walkthrough creates a minimal ESM project, adds one test file, and runs it with the default reporter. It takes a few minutes and requires no configuration.

my-project/
├── package.json
└── src/
    └── math.test.js

File	Purpose
`package.json`	Declares ESM (`"type": "module"`) and the test scripts.
`src/math.test.js`	The first test file, discovered by the default patterns.

1. Write a test file

Create src/math.test.js:

import { describe, it, expect } from '@guchho/test';

describe('math', () => {
  it('adds numbers', () => {
    expect(1 + 1).toBe(2);
  });

  it('subtracts numbers', () => {
    expect(10 - 3).toBe(7);
  });

  it('handles async work', async () => {
    const value = await Promise.resolve(20);
    expect(value).toBeGreaterThan(10);
  });
});

2. Run the tests

npx guchho-test

The default command is run, so this is equivalent to:

npx guchho-test run

Run a specific file:

npx guchho-test run src/math.test.js

Command	What it does
`npx guchho-test`	Discover and run every matching test file.
`npx guchho-test run src/math.test.js`	Run one file.
`npx guchho-test run --filter math`	Run tests whose full name contains `math`.
`npx guchho-test watch`	Rerun affected tests when files change.
`npx guchho-test run --coverage`	Collect V8 coverage.
`npx guchho-test run --reporter=junit`	Produce JUnit XML for CI.
`npx guchho-test run --update`	Create or update snapshots.

3. Understand the output

The default reporter prints each file, each test result, and a summary with pass/fail/skip/todo counts and durations.

Exit codes:

Code	Meaning
`0`	All selected tests passed
`1`	One or more tests failed, or a coverage threshold was not met
`2`	Configuration, CLI, discovery, or execution error

4. Add configuration (optional)

Create guchho.test.config.js in the project root:

import { defineConfig } from '@guchho/test';

export default defineConfig({
  include: ['src/**/*.test.js'],
  timeout: 5000,
  reporters: ['default'],
});

See Configuration for the full schema.

What you just built

You now have a discovered test file, a working CLI invocation, and an optional configuration file. From here, add assertions, lifecycle hooks, mocks, and snapshots as your test suite grows.

More examples

Lifecycle hooks

import { describe, it, expect, beforeEach } from '@guchho/test';

describe('counter', () => {
  let count;

  beforeEach(() => {
    count = 0;
  });

  it('starts at zero', () => {
    expect(count).toBe(0);
  });
});

Mocks

import { it, expect, mock } from '@guchho/test';

it('calls the logger', () => {
  const log = mock.fn();

  log('ready');

  expect(log).toHaveBeenCalledWith('ready');
  expect(log).toHaveBeenCalledTimes(1);
});

Snapshots

import { it, expect } from '@guchho/test';

it('matches the expected shape', () => {
  expect({ name: 'guchho', stable: true }).toMatchSnapshot();
});

5. Explore more

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