Abstract:

The practice of using Mock Objects in automated software testing is examined from a critical point of view and found to be highly problematic. Opinions of some well known industry speakers are cited. The supposed benefits of Mock Objects are shown to be either no real benefits, or achievable via alternative means.

Abstract

An automated software testing technique is presented which solves the fragile test problem of white-box testing by allowing us to ensure that the component-under-test interacts with its collaborators according to our expectations without having to stipulate our expectations as test code, without having the tests fail each time our expectations change, and without having to go fixing test code each time this happens.

Abstract

What are fakes, what are their benefits, and why they are incontestably preferable over mocks. Also, how to create fakes if needed.

Introduction

Over the decades, numerous software system architectures have emerged which require invocations across subsystems to be done via message-passing instead of programmatic interface method calls. Such architectures are so common that many programmers have come to regard message-passing as an end in and of itself, oblivious of the fact that it is nothing but a (poor) technical mechanism for accomplishing a certain architectural goal.

Let me get one thing out of the way first: I am open to Test-Driven Development (TDD). I am not currently practicing it, because when I gave it a try some time ago it did not seem to resonate with me, but I do not have any objections to it in principle, so I might give it another try in the future. Let us just say that it was not love at first sight, but then again some relationships do take some time to warm up.

Having said that, let me now express a few reasons why I am skeptical of TDD. The previous paragraph should have established that I am not trashing TDD, I am just expressing some reservations.

Abstract

A mechanism is described for automatically converting method invocations of any programmatic interface into a single-method normal form and converting back to invocations of the original interface, so that general-purpose operations can be performed on the normal form without explicit knowledge of the interface being invoked. Implementations are provided for C# and for Java.