diff --git a/lib/common/cache_file_store.rb b/lib/common/cache_file_store.rb
index a3121304..c891aefa 100644
--- a/lib/common/cache_file_store.rb
+++ b/lib/common/cache_file_store.rb
@@ -12,14 +12,14 @@ require 'yaml'
 require 'fileutils'
 
 class CacheFileStore
-  attr_reader :storage_path, :serializer
+  attr_reader :storage_path, :cache_dir, :serializer
 
   # The serializer must have the 2 methods .load and .dump
   #   (Marshal and YAML have them)
   # YAML is Human Readable, contrary to Marshal which store in a binary format
   # Marshal does not need any "require"
   def initialize(storage_path, serializer = Marshal)
-    @storage_dir  = File.expand_path(storage_path)
+    @cache_dir    = File.expand_path(storage_path)
     @storage_path = File.expand_path(File.join(storage_path, storage_dir))
     @serializer   = serializer
 
@@ -32,7 +32,7 @@ class CacheFileStore
 
   def clean
     # clean old directories
-    Dir[File.join(@storage_dir, '*')].each do |f|
+    Dir[File.join(@cache_dir, '*')].each do |f|
       if File.directory?(f)
         # delete directory if create time is older than 4 hours
         FileUtils.rm_rf(f) if File.mtime(f) < (Time.now - (60*240))
diff --git a/spec/lib/common/cache_file_store_spec.rb b/spec/lib/common/cache_file_store_spec.rb
index 1fa3523a..d9233512 100644
--- a/spec/lib/common/cache_file_store_spec.rb
+++ b/spec/lib/common/cache_file_store_spec.rb
@@ -30,14 +30,15 @@ describe CacheFileStore do
 
   describe '#clean' do
     it "should remove all files from the cache dir (#{@cache_dir}" do
-      # let's create some files into the directory first
-      (0..5).each do |i|
-        File.new(@cache.storage_path + "/file_#{i}.txt", File::CREAT)
-      end
-
-      expect(count_files_in_dir(@cache.storage_path, 'file_*.txt')).to eq 6
+      # clean is executed by other tests before
+      before = count_files_in_dir(@cache.cache_dir)
+      test_dir = File.expand_path("#{@cache.cache_dir}/test")
+      Dir.mkdir test_dir
+      #change the modification date
+      %x[ touch -t 200701310846.26 #{test_dir} ]
+      expect(count_files_in_dir(@cache.cache_dir)).to eq (before + 1)
       @cache.clean
-      expect(count_files_in_dir(@cache.storage_path)).to eq 0
+      expect(count_files_in_dir(@cache.cache_dir)).to eq before
     end
   end