Testing Inversify Classes

Import privates but don't call them

• Mock them instead before the call

When you are injecting a service that is consumed by a method, do not import or mock downstream dependencies in the service Class constructor

container.snapshot()

Source

// application container is shared by all unit tests
import container from "../../src/ioc/container";

describe("Ninja", () => {
  beforeEach(() => {
    // create a snapshot so each unit test can modify it without breaking other unit tests
    container.snapshot();
  });
  
  afterEach(() => {
    // Restore to last snapshot so each unit test takes a clean copy of the application container
    container.restore();
  });
    
  // each test is executed with a snapshot of the container
  it("Ninja can fight", () => {
    let katanaMock = { 
      hit: () => { return "hit with mock"; }
    };

    container.unbind("Katana");
    container.bind<Something>("Katana").toConstantValue(katanaMock);

    let ninja = container.get<Ninja>("Ninja");

    expect(ninja.fight()).eql("hit with mock");
  });

  it("Ninja can sneak", () => {
    let shurikenMock = { 
      throw: () => { return "hit with mock"; }
    };

    container.unbind("Shuriken");
    container.bind<Something>("Shuriken").toConstantValue(shurikenMock);

    let ninja = container.get<Ninja>("Shuriken");

    expect(ninja.sneak()).eql("hit with mock");
  });
});