函数内的开玩笑模拟测试函数错误：无法读取未定义的属性"id"

Question

选择器

var getId = function getId(state) {
return state.ids.id;
};

这是我要写的函数

export function triggerUpdate() {
store.dispatch(retrieveData(getId(store.getState())));
}

这是我写的测试。但是测试失败了:错误:无法读取未定义的属性"ids"。

describe('triggerUpdate', () => {
it('should call the update', () => {
const expectedPayload = [
{ type: 'RETRIEVE_ID', chorusActions: [] },
];
console.log(store.getState()); // this is coming as empty
const spy = jest.spyOn(store, 'dispatch');
expect(spy).toHaveBeenCalledWith(expectedPayload);
});
});

我需要模拟getId()，但尝试了不同的方法。

Answer 1

const idSelector = require('path');
describe('triggerUpdate', () => {
it('should call the update', () => {
idSelector.getId = jest.fn().mockReturnValue('mockId'); // this is how selector is mocked.
const expectedPayload = [
{ type: 'RETRIEVE_ID', chorusActions: [] },
];
const spy = jest.spyOn(store, 'dispatch');
expect(spy).toHaveBeenCalledWith(expectedPayload[0]);
});
});