createPgliteTestDb

createPgliteTestDb creates an isolated PGlite test database using the template-clone pattern. Migrations run once into an in-memory PGlite instance and the result is dumped; each test gets a cheap clone restored from that dump.

import { createPgliteTestDb } from "@farbenmeer/prisma-migrate-test/pglite";

Peer Dependencies

npm install @electric-sql/pglite pglite-prisma-adapter

Configure your Prisma schema to use the postgresql provider and generate the client with the pglite previewFeature.

API

createPgliteTestDb(options?): PgliteTestDb

Parameters:

Option	Type	Default	Description
migrationsPath	string	"prisma/migrations"	Path to the Prisma migrations folder
extensions	object	{}	PGlite extensions to pass to each instance
seed	string | ((adapter: PrismaPGlite) => Promise<void>)	—	Optional seed data applied after migrations. Pass a SQL string or an async function that receives the Prisma adapter. Runs once when the template is built.

Returns: PgliteTestDb

Method	Returns	Description
getAdapter()	Promise<PrismaPGlite & { reset(): Promise<void> }>	Restores a clone from the dump and returns a new adapter with a reset() method
cleanup()	Promise<void>	Closes all open PGlite instances

Usage

import { createPgliteTestDb } from "@farbenmeer/prisma-migrate-test/pglite";
import { PrismaClient } from "@prisma/client";
import { afterAll, afterEach, beforeAll, beforeEach } from "vitest";

let testDb: PgliteTestDb;
let prisma: PrismaClient;

beforeAll(() => {
  testDb = createPgliteTestDb({ migrationsPath: "prisma/migrations" });
});

afterAll(async () => {
  await testDb.cleanup();
});

beforeEach(async () => {
  prisma = new PrismaClient({ adapter: await testDb.getAdapter() });
});

afterEach(async () => {
  await prisma.$disconnect();
});

Seeding

The seed option populates the template with initial data after migrations run. Since the seed is applied before the dump, every clone includes the seeded data automatically.

SQL string

const testDb = createPgliteTestDb({
  seed: `INSERT INTO "User" (email, name) VALUES ('alice@test.com', 'Alice')`,
});

Function

Use a function to seed via Prisma, which gives you type-safe access to your models:

const testDb = createPgliteTestDb({
  seed: async (adapter) => {
    const prisma = new PrismaClient({ adapter });
    await prisma.user.create({
      data: { email: "alice@test.com", name: "Alice" },
    });
    await prisma.$disconnect();
  },
});

Resetting

The adapter returned by getAdapter() includes a reset() method that truncates all public tables (except _prisma_migrations). This is useful for cleaning up between tests without creating a new clone:

const adapter = await testDb.getAdapter();
const prisma = new PrismaClient({ adapter });

// ... run test ...

await adapter.reset(); // all tables are now empty