test.js

var numTests = 0
  , callback
  , check = function() {
      if (numTests == 3 && callback) {
        callback();
      }
    }
  ;

module.exports = {
  'test A': function(test) {
    test.ok(true);

    numTests++;
    check();
    test.finish();
  },

  'test B': function(test) {
    test.ok(true);

    setTimeout(function() {
      numTests++;
      check();
      test.finish();
    }, 500);
  },

  'test C': function(test) {
    test.ok(true);

    setTimeout(function() {
      numTests++;
      check();
      test.finish();
    }, 500);
  },

  'test D': function(test) {
    callback = function() {
      test.ok(true);
      test.finish();
    }

    // just in case things are run serially, check to see if we need run our
    // last test already
    check();
  }
};

if (module == require.main) {
  require('../lib/async_testing').run(__filename, process.ARGV);
}