std.unittests for (final?) review

[Lutger Blijdestijn]

Michel Fortin wrote:

> I'm not sold on the concept. The whole point of this module seems to
> offer a way to replace the built-in assertion mechanism with a
> customized one, with the sole purpose of giving better error messages.
> So we're basically encouraging the use of:
> 
> assertPredicate!"a > b"(a, b, "message");
> 
> instead of:
> 
> assert(a > b, "message");
> 
> It looks like an uglification of the language to me.

As you said, it is all about the error messages, not replacing assert perse. 
So this comparison would be more fair, using the syntax suggested by Andrei:

assertPred!">"(a, b);

vs

assert(a > b, format("a > b failed: [%s] is not > [%s]", a, b) );

If you really want the error message, regular asserts are a bit uglier and 
duplicate code.

Cutting down on the characters further, 'expect' could be used instead of 
assertPred. Some unittest libraries also use this, but I can't remember 
which one. I think it then makes sense to unify everything:

expect!">"(a, b);
expect!Exception( { throw new Exception(""); } () );