diff --git a/lib/appraisal/appraisal.rb b/lib/appraisal/appraisal.rb
index af839bde..b75dbd4b 100644
--- a/lib/appraisal/appraisal.rb
+++ b/lib/appraisal/appraisal.rb
@@ -109,7 +109,7 @@ def relativize
       File.open(lockfile_path, 'w') do |file|
         file.write lockfile_content.gsub(
           / #{current_directory}/,
-          " #{relative_path.to_s}"
+          " #{relative_path}",
         )
       end
     end