BrowserWindow mock type

[Tanimodori]

Describe the bug

The types of Mock of BrowserWindow use vitest internal type MaybeMocked

vite-electron-builder/packages/main/tests/unit.spec.ts

Lines 1 to 24 in 1daa1d5

	import type {MaybeMocked} from 'vitest';
	import {beforeEach, expect, test, vi} from 'vitest';
	import {restoreOrCreateWindow} from '../src/mainWindow';
	import {BrowserWindow} from 'electron';
	/**
	* Mock real electron BrowserWindow API
	*/
	vi.mock('electron', () => {
	const bw = vi.fn() as MaybeMocked<typeof BrowserWindow>;
	// @ts-expect-error It's work in runtime, but I Haven't idea how to fix this type error
	bw.getAllWindows = vi.fn(() => bw.mock.instances);
	bw.prototype.loadURL = vi.fn();
	bw.prototype.on = vi.fn();
	bw.prototype.destroy = vi.fn();
	bw.prototype.isDestroyed = vi.fn();
	bw.prototype.isMinimized = vi.fn();
	bw.prototype.focus = vi.fn();
	bw.prototype.restore = vi.fn();
	return {BrowserWindow: bw};
	});

Fix

Use MockedObject will fix this issue but the type of bw.prototype is any.

import type {MockedObject} from 'vitest';
import {beforeEach, expect, test, vi} from 'vitest';
import {restoreOrCreateWindow} from '../src/mainWindow';

import {BrowserWindow} from 'electron';

/**
 * Mock real electron BrowserWindow API
 */
vi.mock('electron', () => {

  const bw = vi.fn() as MockedObject<typeof BrowserWindow>;
  bw.getAllWindows = vi.fn(() => bw.mock.instances);
  // bw.prototype is any
  bw.prototype.loadURL = vi.fn();
  bw.prototype.on = vi.fn();
  bw.prototype.destroy = vi.fn();
  bw.prototype.isDestroyed = vi.fn();
  bw.prototype.isMinimized = vi.fn();
  bw.prototype.focus = vi.fn();
  bw.prototype.restore = vi.fn();

  return {BrowserWindow: bw};
});

For the strictest typing, use MockedClass which ports the prototype part of BrowerWindow class. Unfortunately there's a bug of MockedClass type in vistest (see vitest-dev/vitest#1730 , basically they put args and returns in wrong positions lol). I have to include a manual fix for that.

import type {Constructable, Mocked, MockInstance} from 'vitest';
import {beforeEach, expect, test, vi} from 'vitest';
import {restoreOrCreateWindow} from '../src/mainWindow';

import {BrowserWindow} from 'electron';

// Manual fix of MockedClass type
// See https://github.com/vitest-dev/vitest/issues/1730
type MockedClass<T extends Constructable> = MockInstance<T extends new (...args: infer P) => any ? P : never, InstanceType<T>> & {
  prototype: T extends {
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      prototype: any;
  } ? Mocked<T['prototype']> : never;
} & T;

/**
 * Mock real electron BrowserWindow API
 */
vi.mock('electron', () => {

  // Use "as unknown as" because vi.fn() does not have static methods
  const bw = vi.fn() as unknown as MockedClass<typeof BrowserWindow>;
  bw.getAllWindows = vi.fn(() => bw.mock.instances);
  bw.prototype.loadURL = vi.fn();
  // Use "any" because the on function is overloaded
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  bw.prototype.on = vi.fn<any>();
  bw.prototype.destroy = vi.fn();
  bw.prototype.isDestroyed = vi.fn();
  bw.prototype.isMinimized = vi.fn();
  bw.prototype.focus = vi.fn();
  bw.prototype.restore = vi.fn();

  return {BrowserWindow: bw};
});

All the fix does not change the runtime behaviors, just types.

[cawa-93]

LGTM. May you make pr?

[Tanimodori]

The MockedClass issue is fixed in vitest-dev/vitest#1735 . Expected to remove the temp fix once the dep version is dumped.