t/io/fs.t See if directory manipulations work
t/io/inplace.t See if inplace editing works
t/io/iprefix.t See if inplace editing works with prefixes
+t/io/nargv.t See if nested ARGV stuff works
t/io/open.t See if open works
t/io/openpid.t See if open works for subprocesses
t/io/pipe.t See if secure pipes work