test_util_api.md

Test Util APIs

ModulaJS ship with a few helper functions to make testing easy.

givenContext({ key: value, ...}, model)

returns a wrapped model which can access those provided context key/values.

import { TestUtil } from 'modulajs';

const model =
  TestUtil.givenContext({
    {
      value1: 'a',
      gettext: a => a
    },
    new Model()
  });

model.getContext('value1') === 'a';
model.getContext('gettext') == a => a;

processAction(model, action)

Apply the action to model, and returns an array of side effects. The first item in side effects is the newModel while the others are other side effect functions. The last function would be a special side effect function for triggering life cycle hooks.

import { createModel, createConstants, TestUtil } from 'modulajs';

const ActionTypes = createConstants('MODEL', {
  CHANGE: null
});

const Model = createModel({
  modelDidUpdate(oldModel, newModel) {
    this.sendZ(oldModel, newModel);
  },

  recvChange() {
    return {
      type: ActionTypes.CHANGE,
      update(model) {
        const newModel = model.set('a', 'b');

        return [
          newModel,
          newModel.sendX,
          newModel.sendY
        ];
      }
    }
  }
});

const model = new Model();
const action = { type: ActionTypes.CHANGE };

const [ newModel, sideEffect1, sideEffect2, lifeCycleSideEffect ] =
  TestUtil.processAction(model, action)

newModel == model.set('a', 'b');
sideEffect1 === newModel.sendX;
sideEffect2 === newModel.sendY;

// lifeCycleSideEffect once been called will return a Promise object
// which we can then chain with a thenable block to make assertions
// make sure we returned the Promise so mocha knows we're running some async tests
return lifeCycleSideEffect().
  then(() => {
    // modelDidUpdate will be triggered
    // sendZ will be called here with model and newModel respectively
  });

createAction(model, action)

return a different version action with internal marks. Usually it's worked together with sender tests, where we assert that dispatch function is called with an action

import { TestUtil } from 'modulajs';
import sinon from 'sinon';

const dispatch = sinon.spy();

const model =
  TestUtil.givenContext(
    { dispatch },
    new Model()
  );

const action = {
  type: 'SOME_TYPE',
  payload: {
    name: 'abc', id: 123
  }
};

const internalAction = TestUtil.createAction(model, action);

model.sendSomeType();

expect(dispatch.calledWith(internalAction)).to.be.true;