diff --git a/mtbp3/stdiso/pdfsummary.py b/mtbp3/stdiso/pdfsummary.py
index 2dd2f38..21b8246 100644
--- a/mtbp3/stdiso/pdfsummary.py
+++ b/mtbp3/stdiso/pdfsummary.py
@@ -16,7 +16,7 @@
 from pypdf import PdfReader
 import os
 import pandas as pd
-from mtbp3 import cdt, util
+from mtbp3 import util
 
 class pdfSummary:
     """
@@ -186,7 +186,7 @@ def show_outline_tree(self, max_itr=5, to_right=False):
         if len(self.outline_list) != 2:
             raise ValueError("self.outline_list should be a length 2 list")
 
-        tree = cdt.ListTree(lst=self.outline_list[0], infmt='dotspace')
+        tree = util.cdt.ListTree(lst=self.outline_list[0], infmt='dotspace')
         return '\n'.join(tree.list_tree(to_right=to_right))
 
 if __name__ == "__main__":
diff --git a/mtbp3/util/util.py b/mtbp3/util/util.py
deleted file mode 100644
index 5f2645a..0000000
--- a/mtbp3/util/util.py
+++ /dev/null
@@ -1,23 +0,0 @@
-#  Copyright (C) 2023-2024 Y Hsu <yh202109@gmail.com>
-#
-#  This program is free software: you can redistribute it and/or modify
-#  it under the terms of the GNU General Public license as published by
-#  the Free software Foundation, either version 3 of the License, or
-#  any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-#  GNU General Public License for more details
-#
-#  You should have received a copy of the GNU General Public license
-#  along with this program. If not, see <https://www.gnu.org/license/>
-
-import os
-
-_ROOT = os.path.abspath(os.path.dirname(__file__))
-def get_data(path):
-    return os.path.join(_ROOT, '../data', path)
-
-if __name__ == "__main__":
-    pass
\ No newline at end of file
diff --git a/tests/test_cdt.py b/tests/test_util_cdt.py
similarity index 100%
rename from tests/test_cdt.py
rename to tests/test_util_cdt.py
diff --git a/tests/test_util_cdtg.py b/tests/test_util_cdtg.py
new file mode 100644
index 0000000..eb2d432
--- /dev/null
+++ b/tests/test_util_cdtg.py
@@ -0,0 +1,33 @@
+import unittest
+import warnings
+from mtbp3.util.cdtg import catPlotter
+import pandas as pd
+
+class TestCatPlotter(unittest.TestCase):
+
+    def setUp(self):
+        self.df = pd.DataFrame({
+            'Group': ['A', 'A', 'B', 'B', 'C', 'C'],
+            'Value': [1, 2, 3, 4, 5, 6],
+            'Grid': ['G1', 'G1', 'G2', 'G2', 'G1', 'G1'],
+            'CValue': ['C1', 'C2', 'C1', 'C2', 'C1', 'C2'],
+            'CValueGroup': [1, 1, 2, 2, 1, 1]
+        })
+
+    def test_boxplot(self):
+        warnings.filterwarnings("ignore")
+        plotter = catPlotter(self.df, y_col='Value', group_col='Group', x_col='CValue', grid_col='Grid')
+        plotter.boxplot()
+
+    def test_lineplot(self):
+        plotter = catPlotter(self.df, y_col='Value', group_col='Group', x_col='CValue', grid_col='Grid')
+        plotter.lineplot()
+
+    def test_update_parameters(self):
+        plotter = catPlotter(self.df, y_col='Value', group_col='Group', x_col='CValue', grid_col='Grid')
+        plotter.update_parameters(y_col='NewValue', fig_size_0=10)
+        self.assertEqual(plotter.y_col, 'NewValue')
+        self.assertEqual(plotter.fig_size_0, 10)
+
+if __name__ == "__main__":
+    unittest.main()
\ No newline at end of file
diff --git a/tests/test_lsr.py b/tests/test_util_lsr.py
similarity index 100%
rename from tests/test_lsr.py
rename to tests/test_util_lsr.py