Unit test practices in Phobos

[Lars T. Kyllingstad]

Daniel Keep wrote:
> 
> Lars T. Kyllingstad wrote:
>> ...
> 
> Knocked this up in about two minutes.  Might be handy.
> 
> template TestInstantiateImpl(alias Tmpl, Ts...)
> {
>     static if( Ts.length > 0 )
>     {
>         alias Tmpl!(Ts[0]) test;
>         alias TestInstantiateImpl!(Tmpl, Ts[1..$]).next next;
>     }
>     else
>     {
>         enum next = true;
>     }
> }
> 
> template TestInstantiate(alias Tmpl, Ts...)
> {
>     alias TestInstantiateImpl!(Tmpl, Ts).next TestInstantiate;
> }
> 
> template Blah(T)
> {
>     pragma(msg, "Blah!("~T.stringof~")");
>     alias T Blah;
> }
> 
> T nanFor(T)()
> {
>     pragma(msg, "nanFor!("~T.stringof~")");
>     return T.nan;
> }
> 
> unittest
> {
>     static assert( TestInstantiate!(Blah, float, double, real) );
>     static assert( TestInstantiate!(nanFor, float, double, real) );
> 
>     static assert( TestInstantiate!(Blah, int) );
>     static assert( TestInstantiate!(nanFor, int) );
> }
> 
> void main()
> {
> }
> 
> $ dmd -unittest irc
> Blah!(float)
> Blah!(double)
> Blah!(real)
> nanFor!(float)
> nanFor!(double)
> nanFor!(real)
> Blah!(int)
> nanFor!(int)
> irc.d(34): Error: no property 'nan' for type 'int'
> irc.d(43): Error: template instance irc.TestInstantiate!(nanFor,int)
> error instantiating


Good idea. :) Without having tested it, I think your template also works 
with multi-parameter templates:

     template Foo(T, U, V)  { ... }

     unittest
     {
         static assert (TestInstantiate!(Foo, Tuple!(int, real, real),
             Tuple!(uint, double, cdouble)));
     }

If something like this was to go into a library, I'd remove the 
pragma(msg)s, though. They'd get pretty annoying after a while. ;)

-Lars