1 files changed, 9 insertions, 0 deletions
diff --git a/activesupport/test/caching_test.rb b/activesupport/test/caching_test.rb
index 6bb13ec9b8..6b113594cc 100644
--- a/activesupport/test/caching_test.rb
+++ b/activesupport/test/caching_test.rb
@@ -557,6 +557,15 @@ class FileStoreTest < ActiveSupport::TestCase
     key = @cache_with_pathname.send(:key_file_path, "views/index?id=1")
     assert_equal "views/index?id=1", @cache_with_pathname.send(:file_path_key, key)
   end
+  
+  # Because file systems have a maximum filename size, filenames > max size should be split in to directories
+  # If filename is 'AAAAB', where max size is 4, the returned path should be AAAA/B
+  def test_key_transformation_max_filename_size
+    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}B"
+    path = @cache.send(:key_file_path, key)    
+    assert path.split('/').all? { |dir_name| dir_name.size <= ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}
+    assert_equal 'B', File.basename(path)
+  end
 end
 
 class MemoryStoreTest < ActiveSupport::TestCase