Can one customize unit tests?

[PV]

Is it possible to somehow customize syntax and running of unit 
tests?



How I could use it:

1. Running only the tests from recently modified source files.
2. Ability to add optional timeout constraint into the tests, and 
then check whether the test doesn't exceed it.

     unittests (time < 20 ms) { ... }

3. Checking that tests do not leak memory (where applicable).
4. Invoking tests in both D code and in C, where similar 
framework exists.


I'd looked into the documentation, found nothing, but perhaps I 
just missed it. If it is not possible, is it realistic to (very 
easily) hack the D compiler to implement such feature?


Would such feature also work in betterC?