diff --git a/Rakefile b/Rakefile
index 82a1a53541..6ae46a306f 100755
--- a/Rakefile
+++ b/Rakefile
@@ -34,7 +34,7 @@ Rake::TestTask.new(:base_test) do |t|
   t.test_files = if ENV["WIN_RAPID"]
                    ["test/test_event.rb", "test/test_supervisor.rb", "test/plugin_helper/test_event_loop.rb"]
                  else
-                   tests = Dir["test/**/test_*.rb"].sort
+                   tests = Dir["test/plugin/in_tail/test_position_*.rb"].sort
                    if Process.uid.zero?
                      puts "test_file_util.rb for non-root user env. Disable this test on root environment"
                      tests.delete("test/plugin/test_file_util.rb")
diff --git a/test/plugin/in_tail/test_position_file.rb b/test/plugin/in_tail/test_position_file.rb
index 8c9232f878..8ba1be7f7c 100644
--- a/test/plugin/in_tail/test_position_file.rb
+++ b/test/plugin/in_tail/test_position_file.rb
@@ -74,6 +74,7 @@ def write_data(f, content)
 
       @file.seek(0)
       lines = @file.readlines
+      p lines
       assert_equal 4, lines.size
     end
   end