js401-reading

Class 04 Reading - Advanced Mongo/Mongoose

testing mongo

• mocking is sub-optimal as queries can change
• in-memory DB pro/con
  • PRO
  • no mocks needed
  • faster dev: can write just for the test query, don’t need more beyond that
  • testing the code that will be in prod, not an old/incorrect/incomplete mock
  • easy test build: just seed the db and run the code
  • CON
  • need to seed the db
  • uses more memory
  • tests take longer to run

• TOOL: mongodb-memory-server

• create a schema

const productSchema = new mongoose.Schema({
  name: { type: String, required: true},
  price: { type: Number, required: true},
  description: {type: String},
});
<export>

• make the service

<import productModel>
module.exports.create = async (product) => {
  if (!product)
    throw new Error('Missing product');
    await productModel.create(product);
}

• configure jest
• runInBand makes tests run serially

"scripts": {
  "test": "jest --runInBand ./test"
}

• add to package.json

"jest": {
    "testEnvironment": "node"
}

interfaces and repositories

• design patterns are tech agnostic
• biz logic goes to the repository, which THEN goes to the data source, and then back again
• Repository pattern is the container that holds the data
• if you couple that data without using a repository, you can make changing the controller very inflexible or complicated
• using a repo, you can swap out the database and just connect the handlers to without changing the biz logic

This site is open source. Improve this page.