使用 react-testing-library 测试样式组件

Question

我目前正在尝试使用 Mocked Provider 测试样式化组件，如下所示：

import React from "react";
import TestResults from "./TestResults";
import {
  render,
  cleanup,
  findByTestId,
  findByText,
  waitForElement,
} from "@testing-library/react";
import { MockedProvider } from "@apollo/react-testing";




describe("TestResultsComponent", () => {
  describe("Overall", () => {
    it("should render successfully - base", async () => {
      const { getByText } = render(
        <MockedProvider>
          <TestResults />
        </MockedProvider>
      );
      expect(getByText("Preview")).toBeInTheDocument();
    });
  });
});

我在 TestResults 文件中使用 makeStyles 挂钩

当我运行我的测试时，我收到以下错误：

TypeError: theme.spacing is not a function
 Material-UI: the `styles` argument provided is invalid.
      You are providing a function without a theme in the context.
      One of the parent elements needs to use a ThemeProvider.

I'm not sure if I should mock out the implementation of makeStyles. This is the my first time seeing an error like this, I have been testing other components that use the same hook and it has not been an issue.

Answer 1

@material-ui/styles 样式解决方案是独立的，它对 Material-UI 组件一无所知。您需要将 style-components 包中的 ThemeProvider 与核心包中的 const theme = createMuiTheme() 函数一起使用，并在您的测试中呈现它。最好的情况是您已经在应用程序的某处定义了主题，并且可以简单地导入它。

所以你的测试应该变成：

import React from "react";
import {ThemeProvider} from 'styled-components';
import { createMuiTheme } from '@material-ui/core/styles';
import TestResults from "./TestResults";
import {
  render,
  cleanup,
  findByTestId,
  findByText,
  waitForElement,
} from "@testing-library/react";
import { MockedProvider } from "@apollo/react-testing";

describe("TestResultsComponent", () => {
  describe("Overall", () => {
    it("should render successfully - base", async () => {
      const theme = createMuiTheme()
      const { getByText } = render(
        <ThemeProvider theme={muiTheme}>
          <MockedProvider>
            <TestResults />
          </MockedProvider>
        </ThemeProvider>
      );
      expect(getByText("Preview")).toBeInTheDocument();
    });
  });
})

如果这个用于包装组件的样板变得太多，您还可以编写一个 Wrapper-Component 来设置您需要的组件，并将该组件作为第二个参数传递给 render-Options

查看包装器的文档 here

Answer 2

感谢@takethefake 的回答，在我的例子中我们没有使用 MaterialUi 但它非常相似：

import React from 'react';
import { render, screen } from '@testing-library/react';
import { ThemeProvider } from 'styled-components';
import { STRING } from '../constants';
import Theme from '../styles/theme';
import { PreOnboarding } from './PreOnboarding';

test('la valeur `trigger.cta` est utilisée comme fallback du titre', () => {
  const trigger = { cta: 'fallback title', text: STRING.empty };
  const theme = Theme({ color1: 'red', color2: 'blue' });

  render(
    <ThemeProvider theme={theme}>
      <PreOnboarding trigger={trigger} />
    </ThemeProvider>
  );
  const button = screen.getByRole('label', { name: /fallback title/i });
  expect(button).toBeVisible();
});

使用 react-testing-library 测试样式组件

Testing styled components with react-testing-library

unit-testing

reactjs

react-apollo

apollo-client

react-testing-library