added a test case for RT #63568

test_output/cover/cmp_ok.5.0

@@ -0,0 +1,49 @@
+Reading database from 
+
+
+- ------ ------ ------ ------ ------
+File                                         stmt   bran   cond    sub  total
+- ------ ------ ------ ------ ------
+tests/cmp_ok                                100.0    n/a    n/a  100.0  100.0
+Total                                       100.0    n/a    n/a  100.0  100.0
+- ------ ------ ------ ------ ------
+
+
+Run: 
+Perl version: 
+OS: 
+Start: 
+Finish: 
+
+tests/cmp_ok
+
+line  err   stmt   bran   cond    sub   code
+1                                       #!/usr/bin/perl
+2                                       
+3                                       # test case for RT #63568 https://rt.cpan.org/Public/Bug/Display.html?id=63568
+4                                       
+5                                       # 
+6                                       
+7                                       # This software is free.  It is licensed under the same terms as Perl itself.
+8                                       
+9                                       # The latest version of this software should be available from my homepage:
+10                                      # http://www.pjcj.net
+11                                      
+12             1                    1   use Devel::Cover;
+               1                        
+               1                        
+13             1                    1   use Test::More;
+               1                        
+               1                        
+14             1                        cmp_ok('', 'eq', ''); 
+
+
+Covered Subroutines
+-
+
+Subroutine Count Location       
+- ----- ---------------
+BEGIN          1 tests/cmp_ok:12
+BEGIN          1 tests/cmp_ok:13
+
+

tests/cmp_ok

@@ -0,0 +1,14 @@
+#!/usr/bin/perl
+
+# test case for RT #63568 https://rt.cpan.org/Public/Bug/Display.html?id=63568
+
+# Copyright 2004-2011, Paul Johnson (pjcj@cpan.org)
+
+# This software is free.  It is licensed under the same terms as Perl itself.
+
+# The latest version of this software should be available from my homepage:
+# http://www.pjcj.net
+
+use Devel::Cover;
+use Test::More;
+cmp_ok('', 'eq', '');