使用 Jest Enzyme 在 React 中测试带参数的函数

Question

我在反应组件中有一个名为 toggleFilter() 的函数，如下所示：

toggleFilter = (filterType, filterName) => {
        const filterApplied = this.state.appliedFilterList[filterType].includes(filterName);

        if (filterApplied) {
            //Remove the applied filter
            this.setState(prevState => ({
                appliedFilterList: {
                    ...prevState.appliedFilterList,
                    [filterType]: prevState.appliedFilterList[filterType].filter(filter => filter !== filterName)
                }
            }));
        } else {
            //Add the filter
            this.setState(prevState => ({
                appliedFilterList: {
                    ...prevState.appliedFilterList,
                    [filterType]: [...prevState.appliedFilterList[filterType], filterName]
                }
            }));
        }
    };

此函数被传递给子组件：

 <ChildComponent  toggleFilter={this.toggleFilter} />

所以，我想像这样测试这个toggleFilter()函数：

 it("checks for the function calls", () => {
    const toggleFilterMockFn = jest.fn();
    const component = shallow(
        <ProductList
            headerText="Hello World"
            productList={data}
            paginationSize="10"
            accessFilters={["a 1", "a 2"]}
            bandwidthFilters={["b 1", "b 2"]}
            termsFilters={["t 1", "t 2"]}
            appliedFilterList={appliedFilter}
            toggleFilter={toggleFilterMockFn}
        />
    );
    component.find(FilterDropdownContent).prop("toggleFilter")({ target: { value: "someValue" } });
});

但是我收到错误消息：

TypeError: Cannot read property 'includes' of undefined

可能是什么原因导致这个问题？有人可以帮我解决这个问题吗？

编辑1：我尝试了以下测试用例：

expect(toggleFilterMockFn).toHaveBeenCalledWith(appliedFilter, "access");

但是我收到以下错误：

expect(jest.fn()).toHaveBeenCalledWith(expected)

    Expected mock function to have been called with:
      [{"access": ["Access Type Of The Service"], "bandwidth": ["the allowed band width ", "the allowed band width"], "term": ["term associated with the service"]}, "access"]
    But it was not called.

Answer 1

您无法像这样渲染父函数并测试子函数。相反，您应该直接渲染

<FilterDropdownContent />

，然后编写一个测试来模拟事件（如单击）并检查该函数是否被调用。

例如这样的事情：

import React from 'react';
import { shallow } from 'enzyme';

describe('<FilterDropdownContent />', () => {
  let wrapper, toggleFilter;
  beforeEach(() => {
    toggleFilter = jest.fn();
    wrapper = shallow(
      <FilterDropdownContent
        toggleFilter={toggleFilter}
      />
    );
  });

  describe('when clicking the .toggle-filter button', () => {
    it('calls `props.toggleFilter()` with the correct data', () => {
      wrapper.find('.toggle-filter').simulate('click');
      expect(toggleFilter).toHaveBeenCalledWith({ target: { value: 'someValue' } });
    });
  }):
});

在此示例中，单击带有

.toggle-filter

类的链接会调用该函数，但您应该能够根据您的具体实现进行调整。