mocha.js

// test/foo.test.js
var should = require('should');

function Foo() {
  return {
    hoge: function(val) {
      if (val == '') {
        throw new Error('fail');
      }
      return val;
    }
  };
}

var foo = Foo();

describe('Foo', function() {
  describe('#sample1', function() {
    it('equal test', function(){
      foo.hoge('bar').should.equal('bar');
      });
    });
  
  describe('#sample2', function() {
    it('exception test', function(){
      (function(){ foo.hoge('') }).should.throw();
    });
  });
});