如何在 NodeJS 中设置 MongoDB 进行集成测试？

Question

I am writing integration tests for application written in NodeJS with MongoDB.

On CI server I would like to have some sort of embedded MongoDB for faster performance and easier control. Currently I have MongoDB on other server, but tests are slow. Before each test I need to drop all collections. I am using mongoose as ORM.

So far I have only found embedded MongoDB for Java.

Answer 1

As of this writing, I'd recommend using mongodb-memory-server . The package downloads a mongod binary to your home directory and instantiates a new memory-backed MondoDB instance as needed. This should work well for your CI setup because you can spin up a new server for each set of tests, which means you can run them in parallel.

See the documentation for details on how to use it with mongoose.

---

For readers using jest and the native mongodb driver , you may find this class useful:

const { MongoClient } = require('mongodb');
const { MongoMemoryServer } = require('mongodb-memory-server');

// Extend the default timeout so MongoDB binaries can download
jest.setTimeout(60000);

// List your collection names here
const COLLECTIONS = [];

class DBManager {
  constructor() {
    this.db = null;
    this.server = new MongoMemoryServer();
    this.connection = null;
  }

  async start() {
    const url = await this.server.getUri();
    this.connection = await MongoClient.connect(url, { useNewUrlParser: true });
    this.db = this.connection.db(await this.server.getDbName());
  }

  stop() {
    this.connection.close();
    return this.server.stop();
  }

  cleanup() {
    return Promise.all(COLLECTIONS.map(c => this.db.collection(c).remove({})));
  }
}

module.exports = DBManager;

Then in each test file you can do the following:

const dbman = new DBManager();

afterAll(() => dbman.stop());
beforeAll(() => dbman.start());
afterEach(() => dbman.cleanup());

Answer 2

Following the "don't use test doubles for types you don't own" principle, consider continue using a real MongoDB instance for your integration test. Look at this nice article for details.

Answer 3

Our team has been stubbing out the mongo skin calls. Depending on your testing packages you can do the same thing. It takes a little bit of work but it is worth it. Create a stub function and then just declare what you need in your test.

   // Object based stubbing
    function createObjStub(obj) {
      return {
        getDb: function() {
         return {
            collection: function() {
              var coll = {};

              for (var name in obj) {
                var func = obj[name];

                if (typeof func === 'object') {
                  coll = func;
                } else {
                  coll[name] = func;
                }
              }

              return coll;
            }
          };
        }
      }
   }; 
    // Stubbed mongodb call
      var moduleSvc = new ModulesService(createObjStub({
        findById: function(query, options, cb) {
          return cb({
             'name': 'test'
           }, null);
           //return cb(null, null);
        }
      }),{getProperties: function(){return{get: function(){} }; } });