[Rd] testing dontrun examples

[Paul Gilbert]

Is there a good strategy for testing examples which should not be run by 
default? For instance, I have examples which get data from the Internet. 
If I wrap them in try() then they can be skipped if the Internet is not 
available, but may not be tested in cases when I would like to know 
about the failure. (Not to mention that the example syntax is ugly.)

If I mark them \dontrun or \donttest then they are not tested. I could 
mark them \dontrun and then use example() but for this, in addition to 
run.dontrun=TRUE, I would need to specify all topics for a package, and 
I don't see how to do this, missing topic does not work.

Wishlist: what I would really like is R CMD check --run-dontrun   pkg

Suggestions?

Thanks,
Paul