timerstub

Stubbed out timer objects for testing

Timer stub

This is a super simple library to stub out the default javascript timer methods with something that doesn't take any actual time to run. Because slow tests are for suckers!

If you're writing a library which uses timers (like node-browserchannel), its annoying to wait 30 seconds for your timeout event to fire.

npm install timerstub

Add it to your package.json:

  "dependencies"{
    "timerstub": "*"
  }

Timer stub provides a replacement version of setInterval, clearInterval, setTimeout, clearTimeout and Date.now (through a wrapped Date function).

Instead of needing to spend real time waiting for your queued methods to be called, you can now just call timerstub.wait 1000, -> done() to 'wait' 1000 milliseconds. Any queued intervals and timeouts will be called (in order) before your callback is called. Oh yeah, and Date.now() will return the right values in all the callbacks. As far as your library is concerned, 1000 milliseconds have really passed. But your test runs as fast as your CPU can manage it.

In your library, write something like this:

var setInterval, clearInterval, setTimeout, clearTimeout, Date;
function setTimeFunctions(source) {
  setInterval = source.setInterval;
  clearInterval = source.clearInterval;
  setTimeout = source.setTimeout;
  clearTimeout = source.clearTimeout;
  Date = source.Date;
};
setTimeFunctions((function() { return this; })()); // Use the normal ones. 
exports.setTimeFunctions = setTimeFunctions;
 
 
// ... Then write the rest of your code as normal. 
exports.coolstuff = function() {
    var timer = setTimeout(function() { foo(); }, 1000);
    var start = new Date();
    time = Date.now();
    clearTimeout(timer);
  // ... 
}

In a testing framework like mocha:

timerstub = require 'timerstub'
assert = require 'assert'
mycoollibrary = require './mycoollibrary'
 
mycoollibrary.setTimeFunctions timerstub
 
describe 'my cool thing'
    beforeEach ->
        timerstub.clearAll() # This removes all queued timeouts and whatnot 
 
    it 'does cool stuff': (done) ->
        mycoollibrary.coolstuff()
        timerstub.wait 1000->
            # Now 1000 milliseconds of setInterval calls and stuff have run... instantly! 
            assert.strictEqual you.sexytrue
            done()

In a parallel testing framework like expresso, simply add a call to timerstub.waitAll() after all your tests have been scheduled. (In expresso, that would be in a beforeExit block).

testtimers should be compatible with all the testing frameworks - it doesn't interfere with the testing framework at all.


Licensed under the standard MIT license:

Copyright 2011 Joseph Gentle.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.