bahmutov/lazy-ass

import { lazyAss } from '../src'

describe('function as condition', function() {
  it('evaluates the function', function() {
    var called
    function condition() {
      called = true
      return true
    }

    lazyAss(condition)
    expect(called).toBe(true)
  })

  it('no result is failure', function() {
    function noreturn() {}

    expect(function() {
      lazyAss(noreturn)
    }).toThrowError()
  })

  it('adds condition function source to message', function() {
    function myCondition() {}
    expect(function() {
      lazyAss(myCondition)
    }).toThrowError(/myCondition/)
  })

  it('allows anonymous functions', function() {
    var called
    lazyAss(function() {
      return true
    })
    lazyAss(function() {
      return true
    }, 'everything is ok')
    lazyAss(function() {
      called = true
      return true
    }, 'everything is ok')
    expect(called).toBe(true)

    expect(function() {
      lazyAss(function() {})
    }).toThrowError()
  })

  it('has access via closure', function() {
    var foo = 2,
      bar = 3
    expect(function() {
      lazyAss(function() {
        return foo + bar === 6
      }, 'addition')
    }).toThrowErrorMatchingSnapshot()
  })

  it('example', function() {
    var foo = 2,
      bar = 2
    function isValidPair() {
      return foo + bar === 4
    }
    lazyAss(isValidPair, 'foo', foo, 'bar', bar)
  })
})