boginw/jest-ts-auto-mock

Jest test utility with automatic mock creation for interfaces and classes

Jest Ts Auto Mock

This is a library that extend ts-auto-mock to be used with jest

The intention of the library is to automatically assign jest mock to functions giving you type safety

Requirements

typescript@^3.2.2
ts-jest@>=24 <27

Installation

• A Transformer needs to be provided at compile time. We need to tell ts-jest to use ttypescript that allow us to use a transformer.

IMPORTANT:

• set "cacheBetweenTests" as false

• Add the transformer to your ts config

  {
    "compilerOptions": {
      ...
      "plugins": [
        { "transform": "ts-auto-mock/transformer", "cacheBetweenTests": false }
      ]
    }
  }

  • Enable ttypescript into the ts-jest configuration

     ...
     "globals": {
        "ts-jest": {
          "compiler": "ttypescript"
        }
      }

• provide jest-ts-auto-mock config before your test

"jest": {
    ...
    "setupFiles": [
      "<rootDir>/config.ts"
    ]
   ...
  },

• config file

import 'jest-ts-auto-mock'

Examples

ts-jest-ttypesctipt

Usage

1. create an interface

interface Interface {
    methodToMock: () => string
}

2. create a mock

const mock: Interface = createMock<Interface>();

3. get the method mock

You can get the method spy in 2 different ways

Through method

import { On, method } from "ts-auto-mock/extension";
const mockMethod: Jest.Mock = On(mock).get(method(mock => mock.methodToMock));

Through string

import { On, method } from "ts-auto-mock/extension";
const mockMethod: Jest.Mock = On(mock).get(method('methodToMock'));

4. trigger the method

someMethodThatWillTriggerInterfaceA();
expect(mockMethod).toHaveBeenCalled();

Authors

• Vittorio Guerriero
• Giulio Caprino

License

This project is licensed under the MIT License