prismock

Install prismock as a development dependency after you have already set up Prisma in your project.

# Using npm
$ npm add --save-dev prismock

# Using yarn
$ yarn add -D prismock

If your Prisma client is generated to a custom directory (using the output field in your Prisma generator) instead of the default node_modules/.prisma/client, you cannot use the standard PrismockClient. Instead, you must use createPrismock and pass the Prisma object exported from your custom client path.

Note that automatic mocking via the __mock__ directory only works if the client is generated in node_modules.

import { createPrismock } from 'prismock';
import { Prisma } from './prisma/custom-client';

import { PrismaService } from './prisma.service';

const PrismockClient = createPrismock(Prisma);
const prismock = new PrismockClient();
const app = createApp(prismock);

Starting from version v1.13.0, the functions generatePrismock and generatePrismockSync are deprecated and will be removed in a future version. You should replace them with the PrismockClient class. PrismockClient allows you to mock the PrismaClient directly, is easier to use because it does not rely on async functions for generation, and can be extended via class inheritance.

// Instead of generatePrismock, use PrismockClient
import { PrismockClient } from 'prismock';

const prismock = new PrismockClient();

To automatically mock Prisma in your tests (compatible with Jest and Vitest), create a __mocks__/@prisma/client.ts (or .js) file at your project root. In this file, re-export everything from @prisma/client but replace PrismaClient with PrismockClient from prismock.

import { PrismockClient } from 'prismock';

export * from '@prisma/client';
export { PrismockClient as PrismaClient };

The data property in UpdateArgs supports several powerful nested operations for relational fields:

• connect: Connects an existing record to the current item.
• connectOrCreate: Attempts to connect an existing record or creates a new one if it doesn't exist.
• create / createMany: Creates new related records.
• update / updateMany: Updates existing related records.
• upsert: Updates a record if it exists, otherwise creates it.

For list fields, you can also use:

• push: Appends items to an existing list.

For scalar fields, you can use atomic arithmetic operations:

• increment: Adds a value to the current number.
• decrement: Subtracts a value from the current number.
• multiply: Multiplies the current number.
• divide: Divides the current number.
• set: Overwrites the field with a specific value.

If you encounter the error TypeError: jest.requireActual(...).createPrismock is not a function, it usually means your code is importing @prisma/client instead of your custom client path.

To fix this:

1. Ensure all imports in your application and tests point to your custom client directory.
2. Verify that the paths used when instantiating your prismock instance are correct and match your custom output path.

If you prefer to mock the client directly within your test files or setupTests, use jest.mock to replace the real PrismaClient with PrismockClient.

jest.mock('@prisma/client', () => {
  return {
    ...jest.requireActual('@prisma/client'),
    PrismaClient: jest.requireActual('prismock').PrismockClient,
  };
});

You can manually instantiate PrismockClient and pass it to your application services or functions. This is useful for dependency injection in tests.

import { PrismockClient } from 'prismock';
import { PrismaService } from './prisma.service';

const prismock = new PrismockClient();
const app = createApp(prismock);

To use prismock as a replacement for the real PrismaClient within a Jest testing environment, use jest.mock to intercept the @prisma/client module. This approach replaces the PrismaClient class with PrismockClient while preserving other actual exports from the original package.

jest.mock('@prisma/client', () => {
  return {
    ...jest.requireActual('@prisma/client'),
    PrismaClient: jest.requireActual('prismock').PrismockClient,
  };
});