Pathname#relative_path_from compatible with mock.

[Fix GH-2049]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66416 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 2 deletions

diff --git a/ext/pathname/lib/pathname.rb b/ext/pathname/lib/pathname.rb
index 7fb923c6ae..383d47b52f 100644
--- a/ext/pathname/lib/pathname.rb
+++ b/ext/pathname/lib/pathname.rb
@@ -503,9 +503,13 @@ class Pathname
   # ArgumentError is raised when it cannot find a relative path.
   #
   def relative_path_from(base_directory)
-    base_directory = Pathname.new(base_directory) unless Pathname === base_directory
     dest_directory = self.cleanpath.to_s
-    base_directory = base_directory.cleanpath.to_s
+    base_directory =
+      if base_directory.respond_to? :cleanpath
+        base_directory
+      else
+        Pathname.new(base_directory)
+      end.cleanpath.to_s
     dest_prefix = dest_directory
     dest_names = []
     while r = chop_basename(dest_prefix)