diff --git a/4-testing/17-assertions/test_string_utils.py b/4-testing/17-assertions/test_string_utils.py
index c5e88eb..d946680 100644
--- a/4-testing/17-assertions/test_string_utils.py
+++ b/4-testing/17-assertions/test_string_utils.py
@@ -7,13 +7,27 @@
 class TestStringUtils(unittest.TestCase):
 
   def test_reverse_string(self):
+    # Test cases for reversing a string
     self.assertEqual(reverse_string('mochi'), 'ihcom')
-  
+    self.assertEqual(reverse_string('hello'), 'olleh')
+    self.assertEqual(reverse_string('Python'), 'nohtyP')
+    self.assertEqual(reverse_string(''), '')  # Empty string case
+
   def test_capitalize_string(self):
+    # Test cases for capitalizing a string
     self.assertEqual(capitalize_string('mochi'), 'Mochi')
+    self.assertEqual(capitalize_string('hello'), 'Hello')
+    self.assertEqual(capitalize_string('python'), 'Python')
+    self.assertEqual(capitalize_string('hELLO'), 'Hello')  # Should fix mixed case
+    self.assertEqual(capitalize_string(''), '')  # Empty string case
 
   def test_is_capitalized(self):
-    self.assertTrue(is_capitalized('mochi'))
+    # Test cases for checking if the string is capitalized
+    self.assertTrue(is_capitalized('Mochi'))
+    self.assertFalse(is_capitalized('mochi'))  # This case should return False
+    self.assertTrue(is_capitalized('Hello'))
+    self.assertFalse(is_capitalized('hello'))
+    self.assertFalse(is_capitalized(''))  # Empty string should return False
 
 if __name__ == '__main__':
   unittest.main()