Introduction

FactoryJS provides a plugin for Prisma. By using this plugin, you can automatically generate factories from Prisma schema files.

Installation

To use the Prisma plugin, install the @factory-js/factory and @factory-js/prisma-factory packages. Run the following command to install the packages:

pnpm add -D @factory-js/factory @factory-js/prisma-factory

Setup

After installing the packages, add the generator setting to your Prisma schema file as follows:

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}
 
generator client {
  provider = "prisma-client-js"
}
 
generator factory {
  provider = "prisma-factory"
}
 
...

The setup is now complete. Let's generate the factories. Run the following command to generate the factories in the ./generated/factories.ts directory:

prisma generate

Usage

To use the automatically generated factories, import them from ./generated/factories.ts as shown below. Use .create to create objects.

import { defineUserFactory } from "./generated/factories";
import { PrismaClient } from "@prisma/client";
 
const db = new PrismaClient();
const userFactory = await defineUserFactory(db);
 
it("returns an admin user", async () => {
  const user = userFactory.props({ role: () => "ADMIN" }).create();
  expect(user.role).toBe("ADMIN");
});

The Prisma plugin not only creates the model but also handles one-to-one and one-to-many relationships required for the model when you call .create, saving them all to the database. Therefore, you typically do not need to specify relationships. However, there may be cases where you want to change the relationships for a specific test case. In such cases, you can use .vars to change them. The example below changes the relationship to create an admin user's profile.

const userFactory = await defineUserFactory(db);
const profileFactory = await defineProfileFactory(db);
 
it("create an admin profile", async () => {
  const user = userFactory.props({ role: () => "ADMIN" }).create();
  const profile = profileFactory.vars({ user: () => user }).create();
  expect(profile.userId).toBe(user.id);
});