sails-hook-rewire

This is a installable sailsjs hook that lets you rewire sails components, when sails is lifted in test environment.

Often during testing you need to stub certain functions inside your sails models/controllers/services, for example a function that makes http calls.

sails-hook-rewire uses the rewire module to replace components already loaded by sails, with their rewired versions.

Installation

npm install sails-hook-rewire --save

Usage

List components you want rewired, in config/rewire.js

/**
 * Configuration to list which sails components to rewire.
 *
 * You can rewire models, polices, adapters, hooks, blueprints, and responses.
 * You can also choose to have models and services rewired in the global object. Sails only injects models and services
 * in the global obejct.
 *
 * @type {Object} 
 */
module.exports.rewire = {
  // List services to be rewired
  services: [
    {
      name: 'FileService',
      global: true    // replace the global FileService with the rewired version
    },
    {
      name: 'FetchService',
      global: false   // don't replace the global FetchService with the rewired version
    }
  ],
  // List controllers to be rewired
  controllers: [
    {
      name: 'FileController'
    },
    {
      name: 'DNSLookUpController',
      global: true    // this does nothing as controllers are not injected into the global object by sails
    }
  ]
};

Rewire your components

Suppose you have a service, FileService, that depends on the fs module, and you want to stub fs.readFile method in the service. Since the service has already been rewired, all you need to do is stub

var expect = require('expect.js'),
  fileServiceRevert;
 
describe('Tests for FileService', function () {
  before(function () {
    fileServiceRevert = FileService.__set__({
      fs: {
        readFile: function (filename, options, callback) {
          var response = {
            err: null,
            data: undefined
          };
 
          callback = typeof options === 'function' && options || callback || function () {};
 
          // Return an error if filename matches error, eg /var/www/jsons/error.json
          filename.match(/error/) && (response.err = new Error('Error reading file'));
 
          // Return a valid JSON string if file matches valid, eg /var/www/jsons/valid.json
          filename.match(/.+\/valid/) && (response.data = '{"valid": true}');
 
          // Return an invalid JSON string if file matches invalid, eg /var/ww/jsons/invalid.json
          filename.match(/.+\/invalid/) && (response.data = '{"invalid": true;');
 
          return callback(response.err, response.data);
        }
      }
    });
  });
 
  after(function () {
    // Revert the rewiring
    fileServiceRevert();
  });
 
  it('handles read error', function (done) {
    FileService.fetchJSONFromFile('/var/www/jsons/error.json', function (err, data) {
      expect(err).to.be.ok();
      expect(err.error instanceof Error).to.be.ok();
      expect(data).to.not.be.ok()
 
      return done();
    });
  });
 
  it('handles invalid json', function (done) {
    FileService.fetchJSONFromFile('/var/www/jsons/invalid.json', function (err, data) {
      expect(err).to.be.ok();
      expect(err.error instanceof Error).to.be.ok();
      expect(data).to.not.be.ok()
 
      return done();
    });
  });
 
  it('returns a json if file has valid json', function (done) {
    FileService.fetchJSONFromFile('/var/www/jsons/valid.json', function (err, data) {
      expect(err).to.not.be.ok();
      expect(data).to.be.ok();
      expect(data).to.be.an('object');
      expect(data.valid).to.be.ok();
 
      return done();
    });
  });
});

Run tests

When running tests, ensure that sails is lifted in the test environment. You can do this by either,

• Setting NODE_ENV to test before the tests are run

export NODE_ENV=test;
npm test;
unset NODE_ENV;

• Passing the environment to sails while loading in a test bootstrap.

var Sails = require('sails'),
  sails;
 
before(function (done) {
  Sails.load({
    environment: 'test'
    // other setting overrides
  },
  function (err, server) {
    if (err) { return done(sails); }
    sails = server;
    return done(null, sails);
  });
});
 
after(function (done) {
  sails.lower(done);
});

Optionally, if you wish to lift your server in test mode, you can pass the environment as an option to sails lift

sails lift --environment=test

For more examples of how to test sails components with rewire, check out the tests for this module.

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This project is licensed under the Apache 2.0 License.

For contributing, please check the contributing guidelines.

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