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trap is simply the most dead-simple test framework you can pick up. It builds and simplifies the already simple structure of of node-tap or tape, but is extensible like mocha.

Get started with

npm install trap

Output Sample

What do I need to know?

Two things: test, and t.cb. It's really that simple. You can use the assertion framework you already know. By default trap uses the standard node assertion library. To run the tests in single file, just node the file.


Like tap, we make new test blocks with the test function.

var test = require('trap').test;
test('This is a test block!', function (t) {
  t.test('This is a child test block!', function (t) {
    // continue to your heart's content. 


Unlike tap, you don't need to figure out when your async tests are done runnning, nor do you need to count how many assertions you have and plan them. Instead, simply register all of your callbacks with t.cb.

var test = require('trap').test;
test('Async stuff', function (t) {
  setTimeout(t.cb(function() {
    t.ok(true, 'This is still part of the "Async stuff" test!');
  }), 100);


If you happen to prefer promises over callbacks, we support that, too! Instead of using t.cb(), perform all of your assertions in a .then(...) continuation and return a promise that encompasses all of the work. Trap will wait for your promise to finish before running the next test. If your promise fails (e.g. unhandled exception), trap will report that as an assertion failure.

var test = require('trap').test;
var Q = require('q'); // I'm using Q here, but you can use any promise-compliant library. 
test('Promise stuff', function(t) {
  var firstFired, secondFired;
  return Q.all([
    Q.delay(100).then(function() {
      firstFired = true;
      t.ok(!secondFired, 'First comes first');
    Q.delay(150).then(function() {
      secondFired = true;
      t.ok(firstFired, 'Second comes second');


To get the maximum prettiness and documentation of trap, customize config.createTextContext to wrap your favorite assertion library. Otherwise you can just throw exceptions like you normally do, and those will be interpreted as assertion failures. Hopefully soon we can get plugins for all the major assertion libraries so this will be even easier.

Batch-Running Tests

Trap has a command-line runner so you can run a whole suite of tests together. First, install trap globally:

npm install -g trap

Then call trap like this:

node-trap [--config /path/to/config] [path1 [path2 [...]]]

The paths may use glob features supported by minimatch. --config defaults to ./test/trap.config.js and path1 defaults to ./test/**/*.trap.js.

Unfortunately, trap is already taken by a bash builtin, so overriding it by default would be a little presumptuous. But, if you happen to not care about the builtin trap function and you really hate typing node-, you can disable the builtin and simultaneously enable trap by calling:

enable -n trap

If you change your mind, you can return to the usual trap functionality with:

enable trap


Check out the examples folder.