testdouble/src/store/calls.js

A minimal test double library for TDD with JavaScript

import _ from '../wrap/lodash'
import argsMatch from '../args-match'
import cloneDeepIfPossible from '../clone-deep-if-possible'
import store from './index'

let callHistory = [] // <-- remember this to pop our DSL of when(<call>)/verify(<call>)
store.onReset(() => { callHistory = [] })

export default {
  log (testDouble, args, context) {
    store.for(testDouble).calls.push({ args, context, cloneArgs: cloneDeepIfPossible(args) })
    return callHistory.push({ testDouble, args, context })
  },

  pop () {
    return _.tap(callHistory.pop(), function (call) {
      if (call != null) {
        store.for(call.testDouble).calls.pop()
      }
    })
  },

  wasInvoked (testDouble, args, config) {
    const matchingInvocationCount = this.where(testDouble, args, config).length
    if (config.times != null) {
      return matchingInvocationCount === config.times
    } else {
      return matchingInvocationCount > 0
    }
  },

  where (testDouble, args, config) {
    return _.filter(store.for(testDouble).calls, function (call) {
      const pastArgs = config.cloneArgs ? call.cloneArgs : call.args
      return argsMatch(args, pastArgs, config)
    })
  },

  for (testDouble) {
    return store.for(testDouble).calls
  }
}