How does D improve design practices over C++?

[Walter Bright]

Christopher Wright wrote:
> The code you need to write for a unittest is a lot smaller for D's 
> builtin unittests than for any other testing system I've seen. That's 
> the only category in which D's unittests win.

Oh, I fully agree that D's unittests are not an advanced or 
comprehensive framework for unit testing. But D's builtin ones have a 
huge advantage - they are built in. That seems to make an awful lot of 
difference in encouraging the writing of unit tests, whereas most C/C++ 
projects I've run across have no unit tests at all. I know that unit 
tests have made for a big improvement in the quality of Phobos.