diff --git a/lib/framework/detector/os_hierarchy.rb b/lib/framework/detector/os_hierarchy.rb
index 0b227df3e..294ae59aa 100644
--- a/lib/framework/detector/os_hierarchy.rb
+++ b/lib/framework/detector/os_hierarchy.rb
@@ -4,7 +4,7 @@ module Facter
   class OsHierarchy
     def initialize
       @log = Log.new(self)
-      json_file = Util::FileHelper.safe_read('os_hierarchy.json')
+      json_file = Util::FileHelper.safe_read(File.join(ROOT_DIR, 'os_hierarchy.json'))
 
       begin
         @json_os_hierarchy = JSON.parse(json_file)
diff --git a/spec/framework/detector/os_hierarchy_spec.rb b/spec/framework/detector/os_hierarchy_spec.rb
index df5daf166..325f4d16e 100644
--- a/spec/framework/detector/os_hierarchy_spec.rb
+++ b/spec/framework/detector/os_hierarchy_spec.rb
@@ -6,7 +6,7 @@
   before do
     allow(Facter::Util::FileHelper)
       .to receive(:safe_read)
-      .with('os_hierarchy.json')
+      .with(File.join(ROOT_DIR, 'os_hierarchy.json'))
       .and_return(load_fixture('os_hierarchy').read)
     allow(Facter::Log).to receive(:new).and_return(log)
   end
@@ -18,7 +18,7 @@
       before do
         allow(Facter::Util::FileHelper)
           .to receive(:safe_read)
-          .with('os_hierarchy.json')
+          .with(File.join(ROOT_DIR, 'os_hierarchy.json'))
           .and_return(load_fixture('broken_os_hierarchy').read)
       end