As a bit of a convention I've taken to calling my variables 'testX' if they are an instance of 'X' that I am testing with.

So here I would name my variable 'testJob' and later when you're checking that the right one has been passed into the closure then It'd be like this:
<pre>
def successHandler = {
   job ->
   successCalled = (job == testJob)
}
</pre>
It's just a suggestion but I find it makes my variable names for these comparisons a bit better (they're still not great)