vi.mock()

Replaces an entire module with a mock version. Useful for mocking external APIs, databases, or third-party libraries.

Syntax

testing

vi.mock("module-name")
vi.mock("module-name", () => ({ ... }))

Example

testing

vi.mock("../lib/emailService", () => ({
  sendEmail: vi.fn().mockResolvedValue({ success: true }),
}));

test("sends welcome email on signup", async () => {
  const { sendEmail } = await import("../lib/emailService");
  await signUp("bob@example.com");
  expect(sendEmail).toHaveBeenCalledWith("bob@example.com", "Welcome!");
});