Setup Prisma Test Envrioment

jest-integration-config.ts

import { join } from 'path';
import { jest } from './package.json';

export default {
  ...jest,
  preset: "ts-jest",
  "testRegex": ".*\\.controller.spec\\.ts$",
  "testEnvironment": join(__dirname, "./prisma/test-prisma.js")
};

package.json

{
  "scripts": {
    "test:integration": "jest --config ./jest-integration-config.ts"
  },
  "jest": {
   "moduleFileExtensions": [
      "js",
      "json",
      "ts"
    ],
    "rootDir": "src",
    "testRegex": ".*\\.service.spec\\.ts$",
    "transform": {
      "^.+\\.(t|j)s$": "ts-jest"
    },
    "collectCoverageFrom": [
      "**/*.(t|j)s"
    ],
    "coverageDirectory": "../coverage",
    "testEnvironment": "node"
  }

}

prisma-test-envrioment.js

/* eslint-disable @typescript-eslint/no-var-requires */

const { Client } = require("pg");
const NodeEnvironment = require("jest-environment-node");
const util = require("util");
const { randomUUID } = require("crypto");
const { join } = require("path");
const exec = util.promisify(require("child_process").exec);

const prismaBinary = join(".", "node_modules", ".bin", "prisma2");

class PrismaTestEnvironment extends NodeEnvironment {
  constructor(config) {
    super(config);

    // Generate a unique schema identifier for this test context
    this.schema = `test_${randomUUID()}`;

    // Generate the pg connection string for the test schema
    this.connectionString = `postgresql://postgres:postgres@localhost:5432/tests?schema=${this.schema}`;
  }

  async setup() {
    // Set the required environment variable to contain the connection string
    // to our database test schema
    process.env.DATABASE_URL = this.connectionString;
    this.global.process.env.DATABASE_URL = this.connectionString;

    // Run the migrations to ensure our schema has the required structure
    await exec(`${prismaBinary} migrate deploy`);

    return super.setup();
  }

  async teardown() {
    // Drop the schema after the tests have completed
    const client = new Client({
      connectionString: this.connectionString,
    });
    await client.connect();
    await client.query(`DROP SCHEMA IF EXISTS "${this.schema}" CASCADE`);
    await client.end();
  }
}

module.exports = PrismaTestEnvironment;