Minimum Viable Testing framework

Usage no npm install needed!

<script type="module">
  import mvt from '';


mvt NPM version js-standard-style Build Status

Minimum Viable Testing framework

A Minimalist Take on AVA's Approach to Testing

Because AVA is awesome. Security alerts on dev dependencies are not awesome. Especially when you use the same test library across dozens of projects. No matter how well maintained a project is, when it contains 300+ dependencies security alerts are going to occur.

But It's Just a Dev Dependency...

What's good about it

  • It has 0 dependencies (1 dev dep, and that's ava :smirk:)
  • It can be called via the mvt cli or by simply calling node [test-file].js
  • It doesn't transpile your code (the code you write is the code we test)

What it lacks (the most notable items)

  • Concurrency
    • That's not a thing here (likely never will be)
  • Transpilation
    • Also not a thing here (definitely never will be)
    • Actually, maybe I should add this to "What's good..."
    • I added it...
  • TAP Reporter
    • Happy to add it if there is any demand
  • A community and product maturity
    • The most crucial elements
    • And the primary reason you may want to stick to AVA

Table of Contents


# Install globally
$ npm install --global mvt

# Install for project
$ npm install --save-dev mvt


# OR
mvt test
# OR
mvt test.js test2.js
# OR
mvt --verbose
# OR
mvt test --verbose
# OR
node test.js --verbose
# etc...
const test = require('mvt')

test.setup({ verbose: true })

test.after(() => console.log('test.after invoked'))

test.before(() => console.log('test.before invoked'))

test(' works', (assert) => {, 1)

test.failing('test.failing and works', (assert) => {

test.todo('test.todo works')

test.skip('test.skip works', (assert) => assert.truthy('skipped'))

test.only('test.only works', (assert) => assert.truthy('only'))

test.bench('test.bench works', (assert) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => resolve(), 200)
}, { samples: 5, max: 300 })



Test Function

The only thing this module exports.

test ( message, testFunction )

Main function, give it a message and a test function. Test function receives the assert object (see below).

  • message: (String) Description of test
  • testFunction: ([Async]Function) Description of test

Setup and Teardown

test.setup ( opts )

Use this to configure your tests.

  • opts: (Object)
    • verbose (Boolean) - Print every test if true

test.before ( callback )

Run this before we start running any tests. [callback can be async]

test.after ( callback )

Run this after we run all tests. [callback can be async]

Test Modifiers

test.only ( message, testFunction )

Tests will only be run on any tests run with this modifier.

test.skip ( message, testFunction )

Skip that test (logical enough).

test.failing ( message, testFunction )

This test must fail. If it passes, we'll fail your whole test suite. Goteem.

test.todo ( message )

This is just a placeholder for your good intentions.

Special Tests

test.bench ( message, testFunction, opts )

Run the testFunction opts.samples || 10 times. If average run duration is more than opts.max || 100 milliseconds fail the test.

  • opts: (Object)
    • samples (Number) - How many times we should run the testFunction
    • max (Number [in ms]) - Maximum average duration threshhold
    • parallel (Boolean) - If Async Func run in parallel, default is false
    • cb (Function) - Called with { msTotal, msAvg } on bench completion


Methods available on assert object passed to testFunction

  • is ( a, b ) - a and b must be identical
  • not ( a, b ) - a and b must not be identical
  • pass () - Passes errydamntime
  • fail () - Fails errydamntime
  • true ( a ) - a must be strictly true
  • false ( a ) - a must be strictly false
  • truthy ( a ) - a must be truthy
  • falsy ( a ) - a must be falsy
  • contains ( a, b ) - JSON.stringify(a) must contain (String)b
  • doesNotContain ( a, b ) - JSON.stringify(a) must not contain (String)b
  • lessThan ( a, b ) - a must be less than b
  • greaterThan ( a, b ) - a must be greater than b
  • deepEqual ( a, b ) - a must be deepEqual to b
  • notDeepEqual ( a, b ) - a must not be deepEqual to b
  • throws ( a ) - a must be a function, and it must throw
  • notThrows ( a ) - a must be a function, and it must not throw
  • throwsAsync ( a ) - a must be an async function, and it must throw
  • notThrowsAsync ( a ) - a must be an async function, and it must not throw


  • If your test file is called with the --verbose flag it will list all passed tests

  • It fails fast and hard with process.exit(1)

  • If you have diff installed as a peer dependency, we'll use that for string diffs. To make them more readable and what not.


MIT © Andrew Carpenter