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Prisma Mock

This is a mock of the Prisma API intended for unit testing. All the data is stored in memory.

The library jest-mock-extended is used, which means that if functionality you need is not implemented yet, you can mock it yourself.

Usage

Simple example how to create a prisma mock instance:

import createPrismaMock from "prisma-mock"

let client

beforeEach(() => {
  client = createPrismaMock()
})

An example how to mock a global prisma instance, as the default export in a "db" directory (like blitzjs):

import createPrismaMock from "prisma-mock"
import { mockDeep, mockReset } from "jest-mock-extended"

jest.mock("db", () => ({
  __esModule: true,
  ...jest.requireActual("db"),
  default: mockDeep(),
}))

import db, { Prisma } from "db"

beforeEach(() => {
  mockReset(db)
  createPrismaMock({}, Prisma.dmmf.datamodel)
})

API

createPrismaMock(
  data: PrismaMockData<P> = {},
  datamodel?: Prisma.DMMF.Datamodel,
  client = mockDeep<P>(),
  options: {
    caseInsensitive?: boolean
  } = {}
): Promise<P>

Arg: data

You can optionally start up a pre-filled db, by passing in an object containing keys for tables, and values as arrays of objects (though using create is preferred). Example:

createPrismaMock({
  user: [
    {
      id: 1,
      name: "John Doe",
      accountId: 1,
    },
  ],
  account: [
    {
      id: 1,
      name: "Company",
    },
  ],
})

Arg: datamodel

The datamodel of the prisma client, value of Prisma.dmmf.datamodel.

Arg: client

A jest-mock-extended instance. If not provided, a new instance is created.

Arg: caseInsensitive

If true, all string comparisons are case insensitive.

Supported features

Most common cases are covered, but not everything. Here is a rough list of the supported features:

Model queries

Model query options

Nested queries

Filter conditions and operators

Relation filters

Scalar list methods

TODO (set, push)

Scalar list filters

TODO (has, hasEvery, hasSome, isEmpty, equals)

Atomic number operations

JSON filters

Attributes

Attribute functions

Referential actions

Prisma Client methods

Contribution

Requirements

Create a .env-cmdrc file in the root of your project with the following content:

{
  "postgres": {
    "PROVIDER": "postgresql",
    "DATABASE_URL": "postgresql://postgres:postgres@localhost:5432/postgres?schema=public"
  }
}

Writing Tests

Create your tests in the __tests__ directory. You can use snapshot testing with either expect(res).toMatchSnapshot() or expect(res).toMatchInlineSnapshot(). This captures the result of your tests in a snapshot, which you can use to compare agains prisma-mock results.

Note: If you choose to use snapshot testing, make shore to first run your tests against the real database to create a snapshot of the expected result.

Running Tests

To run tests against a postgres database, run the following command:

yarn run test:postgres

To run tests against prisma-mock (in-memory database), run:

yarn test