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sequelize-test-helpers

1.1.2 • Public • Published

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A collection of utilities to help with unit-testing Sequelize models and code that needs those models.

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How to use

Prerequisites

This library assumes:

  1. You are using chai — Version 4 or better.
  2. You are using sinon — Version 5 or better.

Installation

Add sequelize-test-helpers as a devDependency:

npm i -D sequelize-test-helpers

Examples

Unit Testing Models

Let's say you have a Sequelize model User as follows:

src/models/User.js

const model = (sequelize, DataTypes) => {
  const User = sequelize.define(
    'User',
    {
      age: {
        type: DataTypes.INTEGER.UNSIGNED
      },
      firstname: {
        type: DataTypes.STRING,
        allowNull: false,
        validate: {
          notEmpty: true
        }
      },
      lastname: {
        type: DataTypes.STRING,
        allowNull: false,
        validate: {
          notEmpty: true
        }
      },
      email: {
        type: DataTypes.STRING,
        allowNull: false,
        unique: true,
        lowercase: true,
        validate: {
          isEmail: true,
          notEmpty: true
        }
      },
      token: {
        type: DataTypes.STRING,
        validate: {
          notEmpty: true
        }
      }
    },
    {
      indexes: [
        { unique: true, fields: ['email'] },
        { unique: true, fields: ['token'] }
      ]
    }
  )
 
  User.associate = ({ Company }) => {
    User.belongsTo(Company)
  }
 
  return User
}
 
module.exports = model

You can use sequelize-test-helpers to unit-test this as follows:

test/unit/models/User.spec.js

const { expect } = require('chai')
 
const {
  sequelize,
  dataTypes,
  checkModelName,
  checkUniqueIndex,
  checkPropertyExists 
= require('sequelize-test-helpers')
 
const UserModel = require('../../src/models/User')
 
describe('src/models/User', () => {
  const User = UserModel(sequelize, dataTypes)
  const user = new User()
 
  checkModelName(User)('User')
 
  context('properties', () => {
    ;['age', 'firstname', 'lastname', 'email', 'token'].forEach(
      checkPropertyExists(user)
    )
  })
 
  context('associations', () => {
    const Company = 'some dummy company'
 
    before(() => {
      User.associate({ Company })
    })
 
    it('defined a belongsTo association with Company', () => {
      expect(User.belongsTo).to.have.been.calledWith(Company)
    })
  })
 
  context('indexes', () => {
    ;['email', 'token'].forEach(checkUniqueIndex(user))
  })
})

Built in checks

Check What it does
checkHookDefined Checks that a particular hook is defined.
checkModelName Checks that the model is named correctly.
checkNonUniqueIndex Checks that a specific non-unique index is defined.
checkPropertyExists Checks that the model has defined the given property.
checkUniqueCompoundIndex Checks that a specific unique compound index is defined.
checkUniqueIndex Checks that a specific unique index is defined.

Checking associations

The various association functions are stubbed so you can simply invoke the the model's associate function in a before block then use sinon's standard expectation syntax to check they were called with the correct values.

hasOne

it("defined a hasOne association with Image as 'profilePic'", () => {
  expect(User.hasOne).to.have.been.calledWith(Image, {
    as: 'profilePic'
  })
})

belongsTo

it('defined a belongsTo association with Company', () => {
  expect(User.belongsTo).to.have.been.calledWith(Company)
})

hasMany

it("defined a hasMany association with User as 'employees'", () => {
  expect(Company.hasMany).to.have.been.calledWith(User, {
    as: 'employees'
  })
})

belongsToMany

it("defined a belongsToMany association with Category through CategoriesCompanies as 'categories'", () => {
  expect(Company.belongsToMany).to.have.been.calledWith(Category, {
    through: CategoriesCompanies,
    as: 'categories'
  })
})

Unit testing code that requires models

Let's say you have a utility function that takes some data and uses it to update a user record. If the user does not exist it returns null. (Yes I know this is a contrived example)

src/utils/save.js

const { User } = require('../models')
 
const save = async ({ id, ...data }) => {
  const user = await User.findOne({ where: { id } })
  if (user) return await user.update(data)
  return null
}
 
module.exports = save

You want to unit-test this without invoking a database connection (so you can't require('src/models') in your test).

This is where makeMockModels, sinon, and proxyquire come in handy.

test/unit/utils/save.test.js

const { expect } = require('chai')
const { match, stub, resetHistory } = require('sinon')
const proxyquire = require('proxyquire')
 
const { makeMockModels } = require('sequelize-test-helpers')
 
describe('src/utils/save', () => {
  const User = { findOne: stub() }
  const mockModels = makeMockModels({ User })
 
  const save = proxyquire('../../../src/utils/save', {
    '../models': mockModels
  })
 
  const id = 1
  const data = {
    firstname: 'Testy',
    lastname: 'McTestface',
    email: 'testy.mctestface.test.tes',
    token: 'some-token'
  }
  const fakeUser = { id, ...data, update: stub() }
 
  let result
 
  context('user does not exist', () => {
    before(async () => {
      User.findOne.resolves(undefined)
      result = await save({ id, ...data })
    })
 
    after(resetHistory)
 
    it('called User.findOne', () => {
      expect(User.findOne).to.have.been.calledWith(match({ where: { id } }))
    })
 
    it("didn't call user.update", () => {
      expect(fakeUser.update).not.to.have.been.called
    })
 
    it('returned null', () => {
      expect(result).to.be.null
    })
  })
 
  context('user exists', () => {
    before(async () => {
      fakeUser.update.resolves(fakeUser)
      User.findOne.resolves(fakeUser)
      result = await save({ id, ...data })
    })
 
    after(resetHistory)
 
    it('called User.findOne', () => {
      expect(User.findOne).to.have.been.calledWith(match({ where: { id } }))
    })
 
    it('called user.update', () => {
      expect(fakeUser.update).to.have.been.calledWith(match(data))
    })
 
    it('returned the user', () => {
      expect(result).to.deep.equal(fakeUser)
    })
  })
})

As a convenience, makeMockModels will automatically populate your mockModels with mocks of all of the models defined in your src/models folder (or if you have a .sequelizerc file it will look for the model-path in that). Simply override any of the specific models you need to do stuff with.

Listing your models

It's useful to be able to generate a list of the names of your models.

const { listModels } = require('sequelize-test-helpers')
 
console.log(listModels()) // will spit out a list of your model names.

Similarly to makeMockModels above, listModels will find all of the models defined in your src/models folder (or if you have a .sequelizerc file it will look for the model-path in that).

Custom models paths and custom file suffixes

By default makeMockModels and listModels will both look for your models in files ending with .js in either the models path defined in .sequelizerc, or in src/models. If however your models are not .js files and the models folder is somewhere else you can pass in a custom models folder path and a custom suffix.

  • listModels(customModelsFolder, customSuffix)

    const modelNames = listModels('models', '.ts')
  • makeMockModels(yourCustomModels, customModelsFolder, customSuffix)

    const models = makeMockModels({ User: { findOne: stub() } }, 'models', '.ts')

Development

Prerequisites

  • NodeJS, version 8.10.0 or better (I use nvm to manage Node versions — brew install nvm.)

Initialisation

npm install

Test it

  • npm test — runs the unit tests
  • npm run test:unit:cov — runs the unit tests with code coverage
  • npm run test:mutants — runs the mutation tests

Lint it

npm run lint

Contributing

Please see the contributing notes.

Thanks

install

npm i sequelize-test-helpers

Downloadsweekly downloads

2,244

version

1.1.2

license

MIT

homepage

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repository

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