privatestate

This module enables files written with the CommonJS module syntax to expose private functions for testing.

getting started

In order to use this module, you must have rewire enabled for all required modules. If you are using browserify, you should enable the browserify transform rewireify. If you are using node, you should use rewire-global.

example

When writing a module, you may have private helper functions:

function helper() {
  return 'helper';
}

var Utils = {
  run: function() {
    return helper();
  }
};

module.exports = Utils;

When we write our tests, we can't access helper when we require our file. privatestate lets us access it.

Expose your function like this:

var privateState = require('privatestate');

function helper() {
  return 'helper';
}

var Utils = {
  run: function() {
    return helper();
  }
};

privateState.exposeForTesting(Utils, ['helper']);

module.exports = Utils;

In our test, we can now access our function:

var utils = require('./utils');
var privateState = require('privatestate');
var sinon = require('sinon');

describe('Utils', function() {
  it('should give us a function', function() {
    var helper = privateState.getForTesting(utils, 'helper');
    assert.isFunction(helper);
  });

  it('should allow us to modify our function and restore', function() {
    privateState.setFunctionForTesting(utils, 'helper', sinon.stub().returns('in test'));

    assert.equal('in test', utils.run());

    privateState.restore(utils);
  });
});