我需要测试一个在浏览器中打开一个新选项卡的功能

openStatementsReport(contactIds) {
  window.open(`a_url_${contactIds}`);
}

我想模拟窗口的打开函数,这样我就可以验证正确的URL被传递给打开函数。

使用笑话,我不知道如何模拟窗口。我试着设置窗口。使用mock函数打开,但这种方式不起作用。下面是测试用例:

it('the correct URL is called', () => {
  window.open = jest.fn();
  statementService.openStatementsReport(111);
  expect(window.open).toBeCalled();
});

但是它给出了误差

expect(jest.fn())[.not].toBeCalled()

jest.fn() value must be a mock function or spy.
    Received:
      function: [Function anonymous]

我应该对测试用例做什么?


当前回答

在Jest中有几种方法可以模拟全局变量:

Use the mockImplementation approach (the most Jest-like way), but it will work only for those variables which has some default implementation provided by jsdom. window.open is one of them: test('it works', () => { // Setup const mockedOpen = jest.fn(); // Without making a copy, you will have a circular dependency problem const originalWindow = { ...window }; const windowSpy = jest.spyOn(global, "window", "get"); windowSpy.mockImplementation(() => ({ ...originalWindow, // In case you need other window properties to be in place open: mockedOpen })); // Tests statementService.openStatementsReport(111) expect(mockedOpen).toBeCalled(); // Cleanup windowSpy.mockRestore(); }); Assign the value directly to the global property. It is the most straightforward, but it may trigger error messages for some window variables, e.g. window.href. test('it works', () => { // Setup const mockedOpen = jest.fn(); const originalOpen = window.open; window.open = mockedOpen; // Tests statementService.openStatementsReport(111) expect(mockedOpen).toBeCalled(); // Cleanup window.open = originalOpen; }); Don't use globals directly (requires a bit of refactoring) Instead of using the global value directly, it might be cleaner to import it from another file, so mocking will became trivial with Jest.

文件。/ . js

jest.mock('./fileWithGlobalValueExported.js');
import { windowOpen } from './fileWithGlobalValueExported.js';
import { statementService } from './testedFile.js';

// Tests
test('it works', () => {
  statementService.openStatementsReport(111)
  expect(windowOpen).toBeCalled();
});

文件。/ fileWithGlobalValueExported.js

export const windowOpen = window.open;

文件。/ testedFile.js

import { windowOpen } from './fileWithGlobalValueExported.js';
export const statementService = {
  openStatementsReport(contactIds) {
    windowOpen(`a_url_${contactIds}`);
  }
}

其他回答

在Jest配置中,添加setupFilesAfterEnv: ["./setupTests.js"],创建该文件,并添加您想要在测试之前运行的代码:

// setupTests.js
window.crypto = {
   .....
};

参考:setupFilesAfterEnv [array]

使用global而不是window:

it('the correct URL is called', () => {
  global.open = jest.fn();
  statementService.openStatementsReport(111);
  expect(global.open).toBeCalled();
});

你也可以试试:

const open = jest.fn()
Object.defineProperty(window, 'open', open);

如果它类似于window.location.href中的窗口位置问题,则不能在测试中更改。#890,你可以尝试(调整):

delete global.window.open;
global.window = Object.create(window);
global.window.open = jest.fn();

你可以试试这个:

import * as _Window from "jsdom/lib/jsdom/browser/Window";

window.open = jest.fn().mockImplementationOnce(() => {
    return new _Window({ parsingMode: "html" });
});

it("correct url is called", () => {
    statementService.openStatementsReport(111);
    expect(window.open).toHaveBeenCalled();
});

在我的组件,我需要访问window.location.search。这是我在Jest测试中所做的:

Object.defineProperty(global, "window", {
  value: {
    location: {
      search: "test"
    }
  }
});

如果窗口属性在不同的测试中必须不同,我们可以将窗口模拟放到函数中,并使其可写,以便在不同的测试中重写:

function mockWindow(search, pathname) {
  Object.defineProperty(global, "window", {
    value: {
      location: {
        search,
        pathname
      }
    },
    writable: true
  });
}

并在每次测试后重置:

afterEach(() => {
  delete global.window.location;
});