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假设我有以下类(class):
export default class Person {
constructor(first, last) {
this.first = first;
this.last = last;
}
sayMyName() {
console.log(this.first + " " + this.last);
}
bla() {
return "bla";
}
}
const Person = require("../Person");
jest.mock('../Person', () => {
return jest.fn().mockImplementation(() => {
return {sayMyName: () => {
return 'Hello'
}};
});
});
let person = new Person();
test('MyTest', () => {
expect(person.sayMyName()).toBe("Hello");
expect(person.bla()).toBe("bla");
})
TypeError: person.bla is not a function
最佳答案
使用 jest.spyOn()
是模拟单个方法并保留其余方法的正确 Jest 方式。实际上有两种略有不同的方法。
1.只在单个对象中修改方法
import Person from "./Person";
test('Modify only instance', () => {
let person = new Person('Lorem', 'Ipsum');
let spy = jest.spyOn(person, 'sayMyName').mockImplementation(() => 'Hello');
expect(person.sayMyName()).toBe("Hello");
expect(person.bla()).toBe("bla");
// unnecessary in this case, putting it here just to illustrate how to "unmock" a method
spy.mockRestore();
});
import Person from "./Person";
beforeAll(() => {
jest.spyOn(Person.prototype, 'sayMyName').mockImplementation(() => 'Hello');
});
afterAll(() => {
jest.restoreAllMocks();
});
test('Modify class', () => {
let person = new Person('Lorem', 'Ipsum');
expect(person.sayMyName()).toBe("Hello");
expect(person.bla()).toBe("bla");
});
jest.spyOn(Person, 'myStaticMethod').mockImplementation(() => 'blah');
关于javascript - 开 Jest : How to mock one specific method of a class,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50091438/
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