diff --git a/oop.py b/oop.py
index 7d1c754..711d94e 100644
--- a/oop.py
+++ b/oop.py
@@ -161,7 +161,11 @@ class Tu:
         word1 = self.input_check(word1)
         word2 = self.input_check(word2)
         bridge_words = self.find_bridge_words(word1, word2)
-        self.print_bridge_words(bridge_words, word1, word2)
+        if bridge_words:
+            self.print_bridge_words(bridge_words, word1, word2)
+            return bridge_words
+        else:
+            return bridge_words
 
     def insert_bridge_words(self, text):
 
diff --git a/test.py b/test.py
new file mode 100644
index 0000000..5cc9070
--- /dev/null
+++ b/test.py
@@ -0,0 +1,70 @@
+import unittest
+
+from oop import Tu
+class TextProcessor(Tu):
+    def __init__(self):
+        super().__init__()
+
+
+
+class TestQueryBridgeWords(unittest.TestCase):
+    def setUp(self):
+        # Initialize a graph for testing
+        self.graph = {
+            'a': {'b': 1, 'c': 2},
+            'b': {'c': 1, 'd': 2},
+            'c': {'d': 1},
+            'x': {},
+            'z': {}
+        }
+        self.processor = TextProcessor()
+        self.processor.generate_directed_dict(self.processor.read_text_file("1.txt"))
+        self.processor.generate_directed_graph()
+
+    def test_valid_bridge_words_exist(self):
+        # Valid equivalence class: bridge words exist
+        result = self.processor.queryBridgeWords('the', 'floor')
+        self.assertIn('forest', result)
+
+    def test_valid_bridge_words_not_exist(self):
+        # Valid equivalence class: no bridge words
+        result = self.processor.queryBridgeWords('on', 'the')
+        self.assertEqual(result, [])
+
+    def test_invalid_word1_not_in_graph(self):
+        # Invalid equivalence class: word1 not in graph
+        result = self.processor.queryBridgeWords('an', 'a')
+        self.assertEqual(result, [])
+
+    def test_invalid_word2_not_in_graph(self):
+        # Invalid equivalence class: word2 not in graph
+        result = self.processor.queryBridgeWords('a', 'an')
+        self.assertEqual(result, [])
+
+    def test_invalid_both_words_not_in_graph(self):
+        # Invalid equivalence class: both words not in graph
+        result = self.processor.queryBridgeWords('an', 'sought')
+        self.assertEqual(result, [])
+
+    def test_edge_case_min_word(self):
+        # Edge case: minimum word
+        result = self.processor.queryBridgeWords('a', 'b')
+        self.assertEqual(result, [])
+
+    def test_edge_case_max_word(self):
+        # Edge case: maximum word
+        result = self.processor.queryBridgeWords('x', 'z')
+        self.assertEqual(result, [])
+
+    def test_edge_case_no_bridge_words(self):
+        # Edge case: no bridge words
+        result = self.processor.queryBridgeWords('new', 'worlds')
+        self.assertEqual(result, [])
+
+    def test_edge_case_single_bridge_word(self):
+        # Edge case: single bridge word
+        result = self.processor.queryBridgeWords('the', 'floor')
+        self.assertIn('forest', result)
+
+if __name__ == '__main__':
+    unittest.main()