Unit testing a function returning void

[Bruno Pagis]

Good morning,
I have the following class:

```
class A {
   int[] array;

   ...

   void print() {
     writeln("array = ", this.array);
   }
}
```

I would like to unit test the print function (yes, I know, not 
very useful on the above example since print is merely a 
duplicate of writeln...). Is there a way to use assert to test 
the output of the print function to stdout? Something like:
```
A myClass= new A;
myClass.array = [1,2];
assert(myClass.print() == "array = [1,2]"); // I know that print 
does not return anything so this is wrong, but you get the idea 
:-)
```
Thanks.