selectively running unittest functions

[Dicebot]

This will work starting with 2.064:

module a;

import std.stdio;

struct ID
{
     string data;
}

@ID("one")
unittest
{
     writeln("1");
}

@ID("two")
unittest
{
     writeln("2");
}

void main()
{
     import std.typetuple;
     alias tests = TypeTuple!( __traits(getUnitTests, a) );

     foreach (test; tests)
     {
         foreach (uda; __traits(getAttributes, test))
         {
             static if (is(typeof(uda) == ID))
             {
                 if (uda == ID("two"))
                     test();
             }
         }
     }
}

It will print stuff twice though because I didn't suppress native 
unittest runner. Didn't actually dwell deep into runtime hooks so 
don't know what is best way to do it (maybe we need one more 
enhancement for it)