Fake - A fake is a generic term which can be used to describe either a stub or a mock object.
A fake can be a stub or a mock depending on the context in which it's used.
Mock - A mock object is a fake object in the system that decides whether or not a unit test has passed or failed. A mock starts out as a Fake until it is asserted against.
Stub - A stub is a controllable replacement for an existing dependency (or collaborator) in the system. By using a stub, you can test your code without dealing with the dependency directly. By default, a fake starts out as a stub.
Stub Example:
var stubOrder = new FakeOrder();var purchase = new Purchase(stubOrder);purchase.ValidateOrders();Assert.True(purchase.CanBeShipped);Mock Example:
var mockOrder = new FakeOrder();var purchase = new Purchase(mockOrder);purchase.ValidateOrders();Assert.True(mockOrder.Validated);The main thing to remember about mocks versus stubs:
Mocks are just like stubs, but you assert against the mock object,
whereas you do not assert against a stub.