describe("mockImplementation", () => { test("function", () => { const mockFn1 = jest.fn().mockImplementation(() => 42); const mockFn2 = jest.fn(() => 42); expect(mockFn1()).toBe(42); expect(mockFn2()).toBe(42); });
test("mock.instances", () => { const mockFn = jest.fn(); const a = new mockFn(); const b = new mockFn(); mockFn.mock.instances[0] === a; mockFn.mock.instances[1] === b; });