Mongohat

Simple MongoDB testing library for NodeJs applications. Inspired by mongo-unit. It works with mongodb-memory-server as a main dependency. The major focus of the package is to simplify the loading of seed data for each test suite, and can refresh the the database to bring back its initial state before the test suite making it easy to test several scenario before calling a .refresh() on the Mongohat instance.

Mongohat methods

The following methods are exposed to make test writing easy and fun again :)

New Mongohat Instance

Every instance created can connect to existing database, and if the database name does not exist it creates a new one. Do not call this in a loop.

MongohatOption {
  dbName?: string;
  dbPath?: string;
  dbPort?: number;
  useReplicaSet?: boolean;
  version?: string;
}
const mongohat = new Mongohat("DATEBASE-NAME", option);

option here is of type MongohatOption

.start(verbose)

This method starts the in-memory server instance. If verbose is true then thelogs from mongodb-memory-server are directly piped to the console output

.load([{...}, {...}], retainPreviousData = false)

This loads in the initial data into the in-memory server. If retainPreviousData is set to true (default is false), then the loaded data is added to the existing data, otherwise it overrides it giving Mongohat a new state.

await mongohat.load({
    inventory: [
      {
        productName: "test",
        qty: 5
      },
      {
        productName: "test",
        qty: 2
      },
      ...
      {
        productName: "John",
        qty: 8
      },
    ],
    products: [
      {
        ...
      },
    ],
  });

.getCollection(collectionName)

This returns a collection object of type Collection<Document>, and can used to further interact with the collection

const inventory = mongohat.getCollection("inventory");
  await inventory.insertOne({
    _id: new ObjectId("56d9bf92f9be48771d6fe5b1"),
    productName: "Collection Insert",
    qty: 78,
  } as unknown as Document);

.refresh()

This method can be called in the afterEach or beforeEach hook of the test suite (or as applicable to your scenario).

beforeEach(async() => {
   await mongohat.refresh();
})

It reverts the state of the test data to the state after the last .load() was called.

.getDBUrl()

This method returns the dynamic connection string assigned to the instance of the mongodb running in-memory. If called before a client is well instantiated it throws an exception. This should be called after the .start() method has completed.

const mongohat = new Mongohat("<DATABASE-NAME>");
  await mongohat.start(false);
  ...
  process.env.DB_URL = mongohat.getDBUrl()
  // refresh your config here