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mockModel

mockModel is a utility function that allows you to easily mock models.

Reference​

mockModel(mock, BaseClass?): Model​

Mock a given model, and return a new instance with the specified properties stubbed.

Parameters​

• mock: The partial implementation of the model to mock. Only the specified Observable properties will be stubbed. The rest will be left undefined.
• BaseClass?: An optional base class to use for the mock. This is useful in cases where your model has helper methods or getters that should be included in the mock.

Returns​

• A new instance of the model with the specified properties stubbed.

Usage​

Stubbing Observable Properties​

The mockModel function allows you to easily stub out Observable properties in a model. Consider the following example:

class AppState {
  public session = new Observable<string | undefined>();
  public isLoggedIn = new MediatorObservable(false).mapSource(session => !!session);
}

The isLoggedIn property is a MediatorObservable that maps the value of the session property to a boolean. When using this model in a test, we don't want to be bothered with the implementation details of the isLoggedIn property. We can easily stub out the isLoggedIn while ignoring the session property by using the mockModel function.

import { mockModel } from 'react-obsidian';

describe('AppState', () => {
  it('should return true if the user is logged in', () => {
    const mockAppState = mockModel({
      isLoggedIn: new Observable(true)
    });

    expect(mockAppState.isLoggedIn.value).toBe(true);
  });
});

Including class methods and getters​

We encourage developers to add helper methods and getters to their models. This is a great way to encapsulate business logic in the domain layer. In order to include these methods in your mocks you can provide a base class to the mockModel function.

Consider the following example. The AppState model has a getter called isLoggedIn that returns a boolean based on the value of the session property.

import { injectHook, Model } from 'react-obsidian';

class AppState extends Model {
  public user = new Observable<User>(); // { firstName: string; lastName: string;}
  public session = new Observable<string>();

  get isLoggedIn(): boolean {
    return !!this.loggedIn.value;
  }
}

In order to include the isLoggedIn getter in the mock, we can provide the AppState class as the second argument to mockModel.

import { mockModel } from 'react-obsidian';

describe('AppState', () => {
  it('should return true if the user is logged in', () => {
    const mockAppState = mockModel({
        session: new Observable('1234')
      },
      AppState // When a base class is provided, the mock will be an instance of that class.
    );

    expect(mockAppState.isLoggedIn).toBe(true);
  });
});