has_Rdiff: Attempt to Detect Whether diff Utility is Available
Description
Checks whether tools::Rdiff issues a warning when
running with useDiff=TRUE and if it does assumes this is because the
diff utility is not available.  Intended primarily for testing purposes.
Usage
has_Rdiff(test.with = tools::Rdiff)
Arguments
- test.with
 
function to test for diff presence with, typically Rdiff