diff --git a/test_symbol_converter.py b/test_symbol_converter.py
index 61c1bb34..300ab755 100644
--- a/test_symbol_converter.py
+++ b/test_symbol_converter.py
@@ -79,7 +79,7 @@ def test_replace_symbol(self):
         self.assertSequenceEqual(expected, result)
 
 
-class TestSymbolConverter(unittest.TestCase):
+class MyLineConverterTesterBase(unittest.TestCase):
     def setUp(self):
         self.input_file_name = 'sample.ipynb'
 
@@ -88,6 +88,12 @@ def setUp(self):
 
         self.file_processor = fu.FileProcessor(self.input_file_name, self.cp)
 
+    def check_process_line(self, source_line, expected):
+        result = self.cp.process_line(source_line)
+        self.assertEqual(expected, result)
+
+
+class TestSymbolConverter(MyLineConverterTesterBase):
     def test_wrap_symbol_name(self):
         result = self.cp.wrap_symbol_name('L_AB_m')
         expected = 'L_{AB}_{m}'
@@ -190,10 +196,6 @@ def test_process_line_11(self):
         self.check_process_line("L_AB = sy.Symbol('L_AB_m', real=True, nonnegative=True)",
                                 "L_AB = sy.Symbol('L_{AB}[m]', real=True, nonnegative=True)")
 
-    def check_process_line(self, source_line, expected):
-        result = self.cp.process_line(source_line)
-        self.assertEqual(expected, result)
-
     def test_process_line_100(self):
         self.check_process_line("L_AB_m, L_AC_m = sy.symbols('L_AB_m, L_AC_m', real=True, nonnegative=True)",
                                 "L_AB_m, L_AC_m = sy.symbols('L_{AB}[m], L_{AC}[m]', real=True, nonnegative=True)")