如何访问和测试Node.js模块中的内部（非导出）函数？

Question

function exported(i) {
   return notExported(i) + 1;
}

function notExported(i) {
   return i*2;
}

exports.exported = exported;

var assert = require('assert'),
    test = require('../modules/core/test');

describe('test', function(){

  describe('#exported(i)', function(){
    it('should return (i*2)+1 for any given i', function(){
      assert.equal(3, test.exported(1));
      assert.equal(5, test.exported(2));
    });
  });
});

Answer 1

rewire模块绝对是答案。

下面是我的代码，用于访问一个未导出的函数，并使用Mocha测试它。

application.js：

function logMongoError(){
  console.error('MongoDB Connection Error. Please make sure that MongoDB is running.');
}

var rewire = require('rewire');
var chai = require('chai');
var should = chai.should();


var app = rewire('../application/application.js');


var logError = app.__get__('logMongoError'); 

describe('Application module', function() {

  it('should output the correct error', function(done) {
      logError().should.equal('MongoDB Connection Error. Please make sure that MongoDB is running.');
      done();
  });
});