An example of how to use `tap` to create unit-tests

unittest.js

var sum = function (a, b, f) { return f(null, a + b) }

var test = require('tap').test;

test('sums 1 and 2', function (t) {
  sum(1, 2, function (err, result) {
    t.notOk(err, 'no error');
    t.equal(result, 3, '1 + 2 should be equal to 3');
    t.end();
  });
});
test('sums 5 and 0', function (t) {
  sum(5, 0, function(err, result) {
    t.notOk(err, 'no error');
    t.equal(result, 5, '5 + 0 should be equal to 3');
    t.end();
  });
});

test('sums 5 and -2', function (t) {
  sum(5, -2, function (err, result) {
    t.notOk(err, 'no error');
    t.equal(result, 3, '5 + -2 should be equal to 3');
    t.end();
  });
});