spok

Checks a given object against a given set of specifications to keep you from writing boilerplate tests.

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spok
Checks a given object against a given set of specifications to keep you from writing boilerplate tests.
const test = require('node:test') 
// or: const test = require('tape') 
// or: const test = require('tap') 
const spok = require('spok')

// this would be returned from a function you are testing
const object = {
    one          : 1
  , two          : 2
  , three        : 3
  , four         : 4
  , helloWorld   : 'hello world'
  , anyNum       : 999
  , anotherNum   : 888
  , anArray      : [ 1, 2 ]
  , anotherArray : [ 1, 2, 3 ]
  , anObject     : {}
}

// custom specification
function hasThreeElements(a) {
  return a.length === 3
}

test('my object meets the specifications', (t) => {
  spok(t, object, {
      $topic      : 'spok-example'
    , one          : spok.ge(1)
    , two          : 2
    , three        : spok.range(2, 4)
    , four         : spok.lt(5)
    , helloWorld   : spok.startsWith('hello')
    , anyNum       : spok.type('number')
    , anotherNum   : spok.number
    , anArray      : spok.array
    , anotherArray : hasThreeElements
    , anObject     : spok.ne(undefined)
  })
})

shot

Installation

npm install spok

Node.js Test Runner

Since Node.js 16.x it includes a built-in test runner.
Spok support this out of the box as follows:
  • it uses the build-in assert module to assert the values
  • it uses the passed t: TestContext to print diagnostic messages that detail the assertions
mad
See ./example/node-test.js and ./example/node-test-nested.jsfor a full examples.

Colors

spok detects if colors should be used in the output in order to avoid breaking TAP compatibility when needed as follows:
  • if FORCE_COLOR env var is set to 1|true colors are ALWAYS
  • if NO_COLOR env var is set to 1|true colors are NEVER used
  • if tests are executed via node --test mytest.js and FORCE_COLOR is not set then colorse are disabled
  • if tests are executed via node mytest.js and NO_COLOR is not set then colors are enabled

Tap/Tape

  • tap and tape provide a t which mirrors the assert module and also prints results and the
diagnostics message to the console, thus spok uses t to perform assertions
See ./example/tape.js and ./example/tape-nested.jsfor a full examples.

Cypress/Chai Expect Support

Spok can be used out of the box with expect, for instance when running tests with cypress.io.
Simply create a custom assert function and pass it to spok. The main difference to running tests with tape is that if a single property in the compared object doesn't match the test fails immediately.
import spok from 'spok'
const t = spok.adapters.chaiExpect(expect)

spok(t, meta, {
  err: null,
  fee: 5000,
  status: {
    Ok: null,
  },
})

cypress-passing
spok(t, meta, {
  err: null,
  fee: 4000,
  status: {
    Ok: null,
  },
})

cypress-failing

Why not just deepEqual?

deepEqual works great for most cases, but in some cases you need more control, i.e.
  • values don't exactly match, but are in a given range
  • you want to provide a predicate to determine if a value is correct or not
  • you only want to check a subset of values contained in the object

Adjusting Print Details

By default spok prints the specification that a particular assertion satisified, i.e. satisfies: spok.range(2, 4). You can turn that off via spok.printSpec = false.
On the other hand if you want more details about the satisified spec do spok.printDescription = true instead to get spok to print things like satisfies: spok.range(2, 4) 2 <= value <= 4.
Specs and descriptions are printed in gray so you can focus on the actual values of the test output.
Table of Contents generated with DocToc
- spok
- spok.any - spok.range - spok.gt - spok.ge - spok.lt - spok.le - spok.ne - spok.gtz - spok.gez - spok.ltz - spok.lez - spok.type - spok.array - spok.arrayElements - spok.arrayElementsRange - spok.number - spok.string - spok.function - spok.definedObject - spok.startsWith - spok.endsWith - spok.test - spok.defined - spok.notDefined

spok provides a few common specification functions. However you can write your own functions as well, just return true if specification was satisfied and false if not (see example above).
If you write a specification function that would be useful to others please add it along with a test and provide a PR.
spok.* comparison function names are derived from bash comparison operators to make them easier to remember.

API

spok

Checks the given specifications against the object.
When the tests are run the actual values are printed to verify visually while each provided specification is validated and a test failure caused if one of them fails.
Parameters
  • t Object which has assertion functions equal and deepEqual (to compare objects) - use
**tap**, **tape**, **assert**, **Node.js TestContext** or any other library that has those and thus is compatible
  • obj Object the object to verify the specifications against
  • specifications Object the specifications to verify

spok.any

Version of spok that is less strict about the relation of the specification type, namely it allows overriding the type manually or derives it from the supplied parameter.
Use ONLY when you cannot adjust the types, so plain spok works.

spok.range

Specififies that the given number is within the given range, i.e. min<= x <=max.
var spec = {
 x: spok.range(1, 2)   // specifies that x should be >=1 and <=2
}

Parameters

spok.gt

Specififies that a number is greater than the given criteria.
var spec = {
 x: spok.gt(1)  // specifies that x should be >1
}

Parameters

spok.ge

Specififies that a number is greater or equal the given criteria.
var spec = {
 x: spok.ge(1)  // specifies that x should be >=1
}

Parameters

spok.lt

Specififies that a number is less than the given criteria.
var spec = {
 x: spok.lt(1)  // specifies that x should be < 1
}

Parameters

spok.le

Specififies that a number is less or equal the given criteria.
var spec = {
 x: spok.le(1)  // specifies that x should be <=1
}

Parameters

spok.ne

Specifies that the value is not equal another.
var spec = {
 x: spok.ne(undefined)  // specifies that x should be defined
}

Parameters
  • value Any criteria

spok.gtz

Specifies that the value is greater than zero
var spec = {
  x: spok.gtz
}

spok.gez

Specifies that the value is greater or equal zero
var spec = {
  x: spok.gez
}

spok.ltz

Specifies that the value is less than zero
var spec = {
  x: spok.ltz
}

spok.lez

Specifies that the value is less or equal zero
var spec = {
  x: spok.lez
}

spok.type

Specifies that the input is of a given type.
var spec = {
 x: spok.type('number')  // specifies that x should be a Number
}

Parameters

spok.array

Specifies that the input is an array.
var spec = {
 x: spok.array  // specifies that x should be an Array
}

spok.arrayElements

Specifies that the input is an array with a specific number of elements
var spec = { x: spok.arrayElements(2) // specifies that x should be an Array with 2 elements }
Parameters

spok.arrayElementsRange

Specifies that the input is an array with a number of elements in a given range
var spec = { x: spok.arrayElementsRange(2, 4) // specifies that x should be an Array with 2-4 elements }
Parameters
  • min Number min number of elements
  • max Number max number of elements

spok.number

Specifies that the input of type number and isNaN(x) returns false.
var spec = {
 x: spok.number  // specifies that x should be a Number
}

spok.string

Specifies that the input is a string.
var spec = {
  x: spok.string  // specifies that x should be a String
}

spok.function

Specifies that the input is a function.
var spec = {
  x: spok.function  // specifies that x should be a function
}

spok.definedObject

Specifies that the input is an object and it is not null.
var spec = {
 x: spok.definedObject  // specifies that x is a non-null object
}

spok.startsWith

Specifies that the string starts with the specified substring.
NOTE: only available with node.js which has an ES6 startsWith function
var spec = {
 x: spok.startsWith('hello')  // specifies that x should start with 'hello'
}

Parameters
  • what String substring the given string should start with

spok.endsWith

Specifies that the string ends with the specified substring.
NOTE: only available with node.js which has an ES6 endsWith function
var spec = {
 x: spok.endsWith('hello')  // specifies that x should start with 'hello'
}

Parameters
  • what String substring the given string should start with

spok.test

Specifies that the string needs to match the given regular expression.
var spec = {
  x: spok.test(/hello$/) // specifies that x should match /hello$/
}

Parameters
  • regex RegExp regular expression against which the string is checked via test

spok.defined

Specifies that a value is defined, i.e. it is neither null nor undefined.
var spec = {
  x: spok.defined
}

spok.notDefined

Specifies that a value is notDefined, i.e. it is either null or notDefined.
var spec = {
  x: spok.notDefined
}

License

MIT