[ruby/fileutils] Just the parent path of the destination symlink should exist

ruby/fileutils@71225b1b46

Author: nobu

lib/fileutils.rb

@@ -739,7 +739,7 @@ def ln_sr(src, dest, target_directory: true, force: nil, noop: nil, verbose: nil
         real_ddirs = fu_split_path(File.realpath(parent))
       else
         destdirs ||= fu_split_path(dest)
-        real_ddirs ||= fu_split_path(File.realpath(dest))
+        real_ddirs ||= fu_split_path(File.realdirpath(dest))
       end
       srcdirs = fu_split_path(s)
       i = fu_common_components(srcdirs, destdirs)

test/fileutils/test_fileutils.rb

@@ -1080,7 +1080,11 @@ def test_ln_sr_not_target_directory
       assert_raise(Errno::EEXIST, Errno::EACCES) {
         ln_sr fname, 'tmp', target_directory: false
       }
-      assert_file.not_exist? File.join('tmp/', File.basename(fname))
+      dest = File.join('tmp/', File.basename(fname))
+      assert_file.not_exist? dest
+      ln_sr fname, dest, target_directory: false
+      assert_file.symlink?(dest)
+      assert_equal("../#{fname}", File.readlink(dest))
     end
   end if have_symlink?