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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();
});
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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");
});