tap-data-provider v0.0.1-beta.0

tap-data-provider

Extends node-tap with a new tests assertion and introduces the concept of "DataProvider" in tests.

Install

npm install tap-data-provider

Usage

The module will add a new tests method which accept the following params:

• name: The name of test, same of the original tap test function
• dataSource: The data with which the tests will be executed.
• fn: A function similar to the original one, but which receives also an input and an expected params

Datasource can be sent in form of array or data provider function. In case of function it must return an array.

The first element of the array will be the input params of the callback function, the second element will be the expected params.

const t = require('tap')
const {tapDecorator} = require('tap-data-provider')

tapDecorator(t)

function sum(number1, number2) {
  return number1 + number2
}

// Data source given as array
const datasource = [
  [{n1: 1, n2: 2}, 3],
  [{n1: 3, n2: 2}, 5],
]
t.tests('sum should return right values', datasource, (t, {n1, n2}, expected) => {
  t.equal(sum(n1, n2), expected)
  t.end()
})

// Data source given as provider function
function sumDataProvider() {
  return [
    [{n1: 1, n2: 2}, 3],
    [{n1: 3, n2: 2}, 5],
  ]
}
t.tests('sum should return right values', sumDataProvider, (t, {n1, n2}, expected) => {
  t.equal(sum(n1, n2), expected)
  t.end()
})

Caveats

The tests method is a custom tap assert and created with t.addAssert() function, and for this reason it must return another assert call.

The consequences of this statement is that the number of assertion using tests method will 2n + 1, with n is the size of the data provided

function sumDataProvider() {
  return [
    [{n1: 1, n2: 2}, 3],
    [{n1: 3, n2: 2}, 5],
  ]
}
t.tests('sum should return right values', sumDataProvider, (t, {n1, n2}, expected) => {
  t.equal(sum(n1, n2), expected)
  t.end()
})
// 5 asserts

t.test('sum should return right values 1', (t) => {
  t.equal(sum(1, 2), 3)
  t.end()
})

t.test('sum should return right values 2', (t) => {
  t.equal(sum(3, 2), 5)
  t.end()
})

// 2 asserts