Unique Index Ignored When Updating With Mongoose + Mockgoose In Nodejs

I'm currently using Mongoose ODM to manage database connections to MongoDB in a NodeJS application, and intercepting the connection using Mockgoose in Mocha tests. I've ran into an

Solution 1:

Probably you are using mockgoose.reset in a test hook (e.g. afterEach). It drops the database and the indexes aren't created again during the execution.

The solution is removing models separately.

Solution 2:

Adding on to Diego's post. Calling mockgoose.helper.reset() in a test hook to probably clear the collections in the temporary store also removes the indexes. You should reset the indexes after calling reset using the snippet below.

await mockgoose.helper.reset()
const db = mongoose.connection
db.modelNames().map(async (model) => {
  await db.models[model].createIndexes()
})

This fixed the problem for me. Hope this helps.

Solution 3:

From the mongoose docs

When your application starts up, Mongoose automatically calls ensureIndex for each defined index in your schema. Mongoose will call ensureIndex for each index sequentially, and emit an 'index' event on the model when all the ensureIndex calls succeeded or when there was an error.

While nice for development, it is recommended this behavior be disabled in production since index creation can cause a significant performance impact. Disable the behavior by setting the autoIndex option of your schema to false, or globally on the connection by setting the option config.autoIndex to false.

Since, mongoose sets the index on start, you got to debug the specific error, why mongoDb is not allowing to index, using the following code

//keeping autoIndex to true to ensure mongoose creates indexes on app start
GallerySchema.set('autoIndex', true);
//enable index debugging
GallerySchema.set('emitIndexErrors', false);
GallerySchema.on('error', function(error) {
  // gets an error whenever index build fails
});
GallerySchema.index({ slug: 1 }, { unique: true });

Also, make sure autoIndex is not set to false as mentioned in the mongoose doc, or better set it true explicitly as done above.

Additonally,

mongoose.set('debug', true);

The debug logging will show you the ensureIndex call it's making for you to create the index.