davesag / Sequelize Test Helpers

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

Related Projects

• sequelize-pg-utilities — Simple utilities that help you manage your Sequelize configuration.

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.
3. Using mocha is also recommended, but as long as you are using chai and sinon this should work with any test runner.

Installation

Add sequelize-test-helpers as a devDependency:

npm i -D sequelize-test-helpers

Examples

Unit testing models created with sequelize.define

Note: See below for how to test models created using Model.init

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 with mocha 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

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.

Testing models created with Model.init

Sequelize also allows you to create models by extending Sequelize.Model and invoking its static init function as follows:

Note: creating your models this way makes it harder to test their use.

const { Model, DataTypes } = require('sequelize')

const factory = sequelize => {
  class User extends Model {}
  User.init(
    {
      firstName: DataTypes.STRING,
      lastName: DataTypes.STRING
    },
    { sequelize, modelName: 'User' }
  )
  return User
}

module.exports = factory

You can test this using sequelize-test-helpers, sinon, and proxyquire.

const { expect } = require('chai')
const { spy } = require('sinon')
const proxyquire = require('proxyquire')
const { sequelize, Sequelize } = require('sequelize-test-helpers')

describe('src/models/User', () => {
  const { DataTypes } = Sequelize

  const UserFactory = proxyquire('src/models/User', {
    sequelize: Sequelize
  })

  let User

  before(() => {
    User = UserFactory(sequelize)
  })

  // It's important you do this
  after(() => {
    User.init.resetHistory()
  })

  it('called User.init with the correct parameters', () => {
    expect(User.init).to.have.been.calledWith(
      {
        firstName: DataTypes.STRING,
        lastName: DataTypes.STRING
      },
      {
        sequelize,
        modelName: 'User'
      }
    )
  })
})

Listing your models

Assuming your src/models/index.js (or your equivalent) exports all your models, it's useful to be able to generate a list of their names.

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

Branches

Branch	Status	Coverage	Audit	Notes
develop				Work in progress
master				Latest stable release

Prerequisites

• NodeJS. 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

Lint it

npm run lint

Contributing

Please see the contributing notes.

Thanks

• Thanks to reallinfo for the logo.