test: add tests for multiline mode restoration after prompt interrupts

tests/basic/test_io.py

@@ -353,6 +353,46 @@ class TestInputOutputMultilineMode(unittest.TestCase):
             # The invalid Unicode should be replaced with '?'
             self.assertEqual(converted_message, "Hello ?World")
 
+    def test_multiline_mode_restored_after_interrupt(self):
+        """Test that multiline mode is restored after KeyboardInterrupt"""
+        io = InputOutput(fancy_input=True)
+        io.prompt_session = MagicMock()
+        
+        # Start in multiline mode
+        io.multiline_mode = True
+        
+        # Mock prompt() to raise KeyboardInterrupt
+        io.prompt_session.prompt.side_effect = KeyboardInterrupt
+        
+        # Test confirm_ask()
+        with self.assertRaises(KeyboardInterrupt):
+            io.confirm_ask("Test question?")
+        self.assertTrue(io.multiline_mode)  # Should be restored
+        
+        # Test prompt_ask()
+        with self.assertRaises(KeyboardInterrupt):
+            io.prompt_ask("Test prompt?")
+        self.assertTrue(io.multiline_mode)  # Should be restored
+
+    def test_multiline_mode_restored_after_normal_exit(self):
+        """Test that multiline mode is restored after normal exit"""
+        io = InputOutput(fancy_input=True)
+        io.prompt_session = MagicMock()
+        
+        # Start in multiline mode
+        io.multiline_mode = True
+        
+        # Mock prompt() to return normally
+        io.prompt_session.prompt.return_value = "y"
+        
+        # Test confirm_ask()
+        io.confirm_ask("Test question?")
+        self.assertTrue(io.multiline_mode)  # Should be restored
+        
+        # Test prompt_ask()
+        io.prompt_ask("Test prompt?")
+        self.assertTrue(io.multiline_mode)  # Should be restored
+
 
 if __name__ == "__main__":
     unittest.main()