prisma-mock

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

• findUnique,
• findUniqueOrThrow,
• findMany,
• findFirst,
• findFirstOrThrow,
• create,
• createMany
• delete,
• update,
• deleteMany,
• updateMany
• upsert
• count
• TODO: aggregate
• TODO: groupBy

Model query options

• distinct
• include
• where
• select
• orderBy
• select: _count

Nested queries

• create
• createMany
• update
• updateMany
• delete
• deleteMany
• connect
• disconnect
• set
• upsert
• TODO: connectOrCreate

Filter conditions and operators

• equals
• gt
• gte
• lt
• lte
• not
• in
• notIn
• contains
• startWith
• endsWith
• AND
• OR
• NOT
• mode
• TODO: search

Relation filters

• some
• every
• none
• TODO: is

Scalar list methods

TODO (set, push)

Scalar list filters

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

Atomic number operations

• increment
• decrement
• multiply
• divide
• set

JSON filters

• path
• string_contains
• string_starts_with
• string_ends_with
• array_contains
• array_starts_with
• array_ends_with

Attributes

• @@id
• @default
• @unique
• @@unique (TODO: no error if duplicate)
• @relation
• @updatedAt: Partially supported, value is set at creation (TODO: update value on update)

Attribute functions

• autoincrement()
• TODO: auto()
• cuid()
• uuid()
• now()
• TODO: dbgenerated()

Referential actions

• onDelete (SetNull, Cascade)
• TODO: onDelete: Restrict, NoAction, SetDefault
• TODO: onUpdate

Prisma Client methods

• $transaction
• $transaction (interactive)
• TODO: $transaction (isolation)

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