diff --git a/tests/unit_tests/converters/test_anthropic_to_invariant.py b/tests/unit_tests/converters/test_anthropic_to_invariant.py
index 718270a..8ca9d2d 100644
--- a/tests/unit_tests/converters/test_anthropic_to_invariant.py
+++ b/tests/unit_tests/converters/test_anthropic_to_invariant.py
@@ -60,6 +60,16 @@ def test_convert_messages_with_tool_call():
                 },
             ],
         },
+        {
+            "role": "user",
+            "content": [
+                {
+                    "type": "tool_result",
+                    "content": "Paris is the capital of France.",
+                    "tool_use_id": "toolu_013btUg7dbaEq7NbPGzw4K9u",
+                }
+            ],
+        },
     ]
 
     converted_messages = convert_anthropic_to_invariant_message_format(messages)
@@ -84,4 +94,9 @@ def test_convert_messages_with_tool_call():
                 }
             ],
         },
+        {
+            "role": "tool",
+            "content": "Paris is the capital of France.",
+            "tool_call_id": "toolu_013btUg7dbaEq7NbPGzw4K9u",
+        },
     ]