链式函数调用的最佳单元测试

Question

我已经为此苦苦挣扎了。单元测试的新手。.我正在尝试模拟-

的单元测试用例

fetchFooter() {
    client.items().type('footer_link')
            .depthParameter(10)
            .toObservable()
            .subscribe((response) => {
                this.setState({
                    resFooter: response.items,
                    resFooterLinked: response.linkedItems,
                });
            });
}

客户在哪里

import { DeliveryClient } from '@kentico/kontent-delivery';

const client = new DeliveryClient({
  projectId: <projectKey>,
  enableAdvancedLogging: false,
});

这是我到目前为止所写的，但是似乎没有用。

const sample = {
  items: {},
  linkedItems: {}
};//this is my response object

describe("testing client", () => {
  const mockClient = {
    items: jest.fn().mockReturnThis(),
    type: jest.fn().mockReturnThis(),
    depthParameter: jest.fn().mockReturnThis(),
    toObservable: jest.fn().mockReturnThis(),
    subscribe: jest.fn().mockReturnThis(),
  };

  const mockProps = {
    client: mockClient,
  };
  const component = mount(
    <Footer mockProps={mockProps} resFooter={true} resFooterLinked={true} />
  );

  describe("Component", () => {
    describe("#componentDidMount", () => {
      it("should mount the component and set state correctly", () => {
        const mockedResponse = sample;
        mockClient.subscribe.mockImplementationOnce((handler) => handler(sample));
        // tslint:disable-next-line: no-string-literal
        component["setState"] = jest.fn();
        component.instance().fetchFooter();
        expect(
          mockClient.items().type().depthParameter().toObservable().subscribe
        ).toBeCalledWith("footer_link");
        // tslint:disable-next-line: no-string-literal
        expect(component["setState"]).toBeCalledWith(sample);
      });
    });
  });
});

我收到一个错误-->

    expect(jest.fn()).toBeCalledWith(...expected)

    Expected: "footer_link"

    Number of calls: 0
也许我在这里缺少一些基础知识。我为此寻找了一种解决方案，但不幸的是，找不到适合我的解决方案。有人能帮忙吗？在此先感谢

我已经为此苦苦挣扎了。单元测试的新手。.我正在尝试模拟-fetchFooter（）{client.items（）。type（'footer_link'）.depthParameter（10）...

Answer 1

如the reference所述，mockReturnThis是以下各项的快捷方式：