microk

microk is a zero-dependency testing library for NodeJS.

microk won't produce any output unless an assertion is false. If an assertion fails the exit code of the program is 1.

Installation

Installation using npm or yarn:

npm install --save-dev microk

or

yarn add --dev microk

Walkthrough

Do quick assertions

This code does not produce any output, the assertion is true so it silently goes on:

const { ok } = require('microk')

let value = 1
ok(value === 1)

Let's introduce an error:

const { ok } = require('microk')
let value = 2
ok(value === 1)
console.log('end')

The code above will print an error, yet it won't stop the execution. The output is:

NOT OK: #1
end

What happened here is that the first ok assertion was not true.

To help you reading the output you can add a label to the ok assertions:

let value = 1
ok(value === 2, 'value is correct')
ok(1 === 2)

The output:

NOT OK: value is correct
NOT OK: #2

ok assertions also support an extra parameter. If this parameter a function, it will be invoked, otherwise it will be printed. Note: the extra argument will only be used if the assertion fails.

let value = 1
ok(value === 2, 'value is correct', value)

or

ok(value === 2, 'value is correct', () => {
    console.log('actual value is', value)
})

Credits

microk share its origin with another vanilla js testing project: tressa by Andrea Giammarchi (WebReflection).

Read more about Andrea's idea: JS Vanilla Test Code Coverage, Vanilla JS Testing — Part II.