Validation checks to test if a given object is closed.
Usage
testClosed(object, errormsg = "This is not a closed set")
checkClosed(object, errormsg = "This is not a closed set")
assertClosed(object, errormsg = "This is not a closed set")
Arguments
object
object to test
errormsg
error message to overwrite default if check fails
Value
If check passes then assert returns object invisibly and test/check
return TRUE. If check fails, assert stops code with error, check returns
an error message as string, and test returns FALSE.