Test Case

ELI5 — The Vibe Check

A test case is one specific scenario you want to check. 'Does the login work with a correct password?' — that's a test case. 'Does it fail with a wrong password?' — that's another test case. Each test() or it() block is one test case.

Real Talk

A test case is an individual test that verifies a specific behavior or scenario. It typically follows the AAA pattern: Arrange the preconditions, Act by calling the code under test, and Assert that the result matches expectations.

Show Me The Code

test('returns 404 when user not found', async () => {
  // Arrange
  const req = { params: { id: 'nonexistent' } };
  const res = { status: jest.fn().mockReturnThis(), json: jest.fn() };

  // Act
  await getUser(req, res);

  // Assert
  expect(res.status).toHaveBeenCalledWith(404);
});

When You'll Hear This

"Write a test case for the empty cart scenario." / "This test case covers the happy path only."