test.js

/* global describe, it */

var assert = require('assert')
var isGenerator = require('./')

describe('is-generator', function () {
  describe('generators', function () {
    it('should return false with non-generators', function () {
      assert(!isGenerator(null))
      assert(!isGenerator(25))
      assert(!isGenerator('test'))
      assert(!isGenerator(/* istanbul ignore next */ function () {}))
      assert(!isGenerator(/* istanbul ignore next */ function * () {}))
    })

    it('should return true with a generator', function () {
      assert(isGenerator((/* istanbul ignore next */ function * () {})()))
    })
  })

  describe('generator functions', function () {
    it('should return false with non-generator function', function () {
      assert(!isGenerator.fn(null))
      assert(!isGenerator.fn(25))
      assert(!isGenerator.fn('test'))
      assert(!isGenerator.fn(/* istanbul ignore next */ function () {}))

      var noConstructorFn = /* istanbul ignore next */ function () {}
      noConstructorFn.constructor = undefined

      assert(!isGenerator.fn(noConstructorFn))
    })

    it('should return true with a generator function', function () {
      assert(isGenerator.fn(/* istanbul ignore next */ function * () { yield 'something' }))
    })
  })
})