Definition: Collaborator

I have been coming across the term collaborator in software literature, and I have been using it too in my own writings, but without having seen it defined. I tried searching for its definition, but could not find any. In UML the term collaboration is vaguely described, but not the term collaborator. After asking on Software Engineering Stack Exchange I was pointed to what is in almost all certainty the original definition, but it turns out that it is very old, and slightly problematic, so I thought I should provide a modern definition here, at the very least for use in my own writings.

Here it goes:

A collaborator is a component invoked by another component to do a job.

(And since the context is software, these are, of course, software components.)

Origin of the term

If you are using mock objects you are doing it wrong.

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.

Collaboration Monitoring

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.

On Test-Driven Development (TDD)

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 work for 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.