Review: A new stab at a potential std.unittests

[Jonathan M Davis]

Updated code: http://is.gd/hqPb2

Okay. As mentioned before, I have helper unit test functions which I use heavily 
in std.datetime and which are pretty much going to have to either end up as 
private helper functions in std.datetime or actually get added in a separate 
module for everyone to use (I'd prefer the latter). My last post on it seems to 
have met with positive feedback overall for the basic idea but not necessarily 
the execution.

In particular, needing to pass LineInfo() to assertExcThrown!() to know the file 
and line number was disliked (though it was by far the best solution that I'd 
been able to come up with). Overall, it's worked quite well, but periodically 
(for reasons that I _still_ don't understand) passing the function as an alias 
didn't work properly (sometimes the template constraint which checked that 
calling the function - exactly how it was called in the code - compiled failed, 
whereas the template would compile if the constraint was removed, which makes no 
sense at all to me). So, there were enough problems in using it and enough 
dislike for how it worked, that I mucked around with it a bit to find a better 
way to do it, and I believe that I've found one. You end up passing the entire 
function call as a string (preferably a WYSIWYG string). So, instead of

assertExcThrown!(Exception, myfunc)(LineInfo(), param1, param2);

you get the much shorter and cleaner

mixin(assertExcThrown!(Exception, `myfunc(param1, param2)`));


It mixes the whole thing in on that one line, so it doesn't affect the line count 
and the call is actually done at the local scope, so it's exactly as if you'd 
written the function call directly in the function (since that's how it gets 
compiled in). It also manages to deal with __FILE__ and __LINE__  internally 
this way without even needing to pass them as default parameters. The one 
downside is that - being a string mixin - it does come with higher compilation 
overhead. But that should improve as the compiler improves ( 
http://d.puremagic.com/issues/show_bug.cgi?id=1382 is likely the main culprit).

The list of functions is unchanged, but a few of them became eponymous templates 
to be mixed in as strings rather than being templated function calls. It is bit 
annoying to have to use mixin to do it, but the result is much cleaner on the 
whole, I believe. So, it's a huge useability change.

In any case, I'm presenting the updated for your review, so tell me what you 
think.

- Jonathan M Davis


P.S. My most recent update of std.datetime doesn't use the updated unit test 
functions yet, so the only examples of how to use them are in the docs and 
source of my unittest module - both of which are included in the link above. 
I'll likely post a version of std.datetime with the updated unit tests later 
today, so if you really want to see the functions used on a larger scale, you 
can check that out then.