diff --git a/test/plugin/test_buf_file_single.rb b/test/plugin/test_buf_file_single.rb
index 56f9b643c9..52419dc668 100644
--- a/test/plugin/test_buf_file_single.rb
+++ b/test/plugin/test_buf_file_single.rb
@@ -142,6 +142,8 @@ def create_driver(conf = TAG_CONF, klass = FluentPluginFileSingleBufferTest::Dum
       chunk = p.generate_chunk(Fluent::Plugin::Buffer::Metadata.new(nil, nil, nil))
 
       assert_equal 4 * 1024 * 1024, chunk.instance_variable_get(:@decompression_size_limit)
+
+      chunk.purge
     end
   end