jsPsych/packages/jspsych/tests/test-utils.ts

import { Class } from "type-fest";

import { JsPsych, JsPsychPlugin } from "../src";
import { TimelineNodeDependencies, TrialResult } from "../src/timeline";
import { PromiseWrapper } from "../src/timeline/util";

jest.mock("../src/JsPsych");

/**
 * A class to instantiate mocked `TimelineNodeDependencies` objects that have additional
 * testing-related functions.
 */
export class MockTimelineNodeDependencies implements TimelineNodeDependencies {
  onTrialStart = jest.fn();
  onTrialLoaded = jest.fn();
  onTrialFinished = jest.fn();

  instantiatePlugin: jest.Mock<JsPsychPlugin<any>>;
  getDisplayElement: jest.Mock<HTMLElement>;
  getDefaultIti: jest.Mock<number>;

  finishTrialPromise: PromiseWrapper<TrialResult>;
  jsPsych: JsPsych; // So we have something for plugins in `instantiatePlugin`

  constructor() {
    this.initializeProperties();
  }

  private displayElement: HTMLDivElement;

  private initializeProperties() {
    this.instantiatePlugin = jest.fn(
      (pluginClass: Class<JsPsychPlugin<any>>) => new pluginClass(this.jsPsych)
    );
    this.getDisplayElement = jest.fn(() => this.displayElement);
    this.getDefaultIti = jest.fn(() => 0);

    this.finishTrialPromise = new PromiseWrapper<TrialResult>();
    this.jsPsych = new JsPsych();

    this.displayElement = document.createElement("div");
  }

  // Test utility functions
  reset() {
    this.initializeProperties();

    this.onTrialStart.mockReset();
    this.onTrialLoaded.mockReset();
    this.onTrialFinished.mockReset();
  }
}