Why does File::Path not respond to 'cover'?

Richard Elberger and I recently received co-maintenance bits on the 
File-Path distribution.  As is my wont, I ran it through Devel::Cover -- 
but was surprised to see that 'cover' reported zero coverage.

#####
$ perl Makefile.PL && make
Generating a Unix-style Makefile
Writing Makefile for File::Path
Writing MYMETA.yml and MYMETA.json
Skip blib/lib/File/Path.pm (unchanged)
Manifying blib/man3/File::Path.3

$ HARNESS_PERL_SWITCHES=-MDevel::Cover make test
PERL_DL_NONLAZY=1 
/home/jkeenan/perl5/perlbrew/perls/perl-5.20.1/bin/perl 
"-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef 
*Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/Path-Class.t .. ok
t/Path.t ........ 1/152 bug487319/symlink for bug487319/symlink: No such 
file or directory at t/Path.t line 369.
t/Path.t ........ ok
t/pod.t ......... skipped: PERL_AUTHOR_TESTING environment variable not 
set (or zero)
t/taint.t ....... ok
All tests successful.
Files=4, Tests=190,  1 wallclock secs ( 0.04 usr  0.00 sys +  0.99 cusr 
  0.03 csys =  1.06 CPU)
Result: PASS

$ cover
Reading database from /home/jkeenan/gitwork/File-Path/cover_db


----------------------------------- ------ ------ ------ ------ ------ 
------
File                                  stmt   bran   cond    sub   time 
total
----------------------------------- ------ ------ ------ ------ ------ 
------
blib/lib/File/Path.pm                  0.0    0.0    0.0    0.0    n/a 
   0.0
Total                                  0.0    0.0    0.0    0.0    n/a 
   0.0
----------------------------------- ------ ------ ------ ------ ------ 
------


HTML output written to 
/home/jkeenan/gitwork/File-Path/cover_db/coverage.html
done.
#####

I hypothesized that perhaps results would be different if I were to move 
./Path.pm to lib/File/Path.pm -- but I got the same results.

Does anyone know why File-Path is unresponsive to 'cover'?

Thank you very much.
Jim Keenan