Test struct
          #include <darts/test.h>
        
        Base class for unit tests in Darts.
Derived classes
- struct IntersectionTest
 - A class to test the results of a ray-surface intersection.
 
Public functions
- void run() pure virtual
 - Run the actual test.
 
Function documentation
              void Test:: run() pure virtual
            
            Run the actual test.
This is where all the work happens. Derived classes should override this function.