fix: Black formatting + add coverage for common_utils and responses transformer

- Fix Black formatting in responses/transformation.py (vision log line)
- Add tests for get_copilot_default_headers (with/without conversation key)
- Add tests for get_complete_url, supports_native_websocket,
  validate_environment error paths, map_openai_params

litellm/llms/github_copilot/responses/transformation.py

@@ -115,9 +115,7 @@ class GithubCopilotResponsesAPIConfig(OpenAIResponsesAPIConfig):
         # Add vision header if input contains images
         if self._has_vision_input(input):
             headers["copilot-vision-request"] = "true"
-            verbose_logger.debug(
-                "GitHub Copilot Responses API: Enabled vision request"
-            )
+            verbose_logger.debug("GitHub Copilot Responses API: Enabled vision request")
 
         # Call parent to get request body (validates input, handles reasoning items)
         return super().transform_responses_api_request(

tests/test_litellm/llms/github_copilot/responses/test_github_copilot_responses_transformation.py

@@ -578,3 +578,61 @@ class TestEncryptedContentEdgeCases:
         assert (
             result1["encrypted_content"] != result2["encrypted_content"]
         ), "Each reasoning item must preserve its own encrypted_content independently"
+
+
+class TestResponsesAPIMiscMethods:
+    """Cover misc methods with low coverage in responses/transformation.py."""
+
+    def setup_method(self):
+        self.config = GithubCopilotResponsesAPIConfig()
+
+    def test_supports_native_websocket_is_false(self):
+        assert self.config.supports_native_websocket() is False
+
+    def test_get_complete_url_default_base(self, mock_authenticator_class):
+        url = self.config.get_complete_url(api_base=None, litellm_params={})
+        assert url == "https://api.githubcopilot.com/responses"
+
+    def test_get_complete_url_custom_base(self, mock_authenticator_class):
+        url = self.config.get_complete_url(
+            api_base="https://custom.example.com/v1/", litellm_params={}
+        )
+        assert url == "https://custom.example.com/v1/responses"
+
+    def test_validate_environment_no_api_key_raises(self, mock_authenticator_class):
+        mock_authenticator_class.return_value.get_api_key.return_value = None
+        with pytest.raises(AuthenticationError):
+            self.config.validate_environment(
+                headers={}, model="gpt-4", litellm_params=None
+            )
+
+    def test_validate_environment_get_api_key_error_raises(
+        self, mock_authenticator_class
+    ):
+        mock_authenticator_class.return_value.get_api_key.side_effect = GetAPIKeyError(
+            status_code=401, message="key expired"
+        )
+        with pytest.raises(AuthenticationError):
+            self.config.validate_environment(
+                headers={}, model="gpt-4", litellm_params=None
+            )
+
+    def test_validate_environment_with_conversation_key(self, mock_authenticator_class):
+        mock_authenticator_class.return_value.get_api_key.return_value = "test-key"
+        lp = GenericLiteLLMParams(metadata={"copilot_conversation_id": "test-conv"})
+        headers = self.config.validate_environment(
+            headers={}, model="gpt-4", litellm_params=lp
+        )
+        assert "x-conversation-id" in headers
+
+    def test_map_openai_params_returns_dict(self):
+        result = self.config.map_openai_params(
+            response_api_optional_params={"temperature": 0.5},
+            model="gpt-4",
+            drop_params=False,
+        )
+        assert result == {"temperature": 0.5}
+
+    def test_get_supported_openai_params_returns_list(self):
+        result = self.config.get_supported_openai_params("gpt-4")
+        assert isinstance(result, list)

tests/test_litellm/llms/github_copilot/test_conversation_id.py

@@ -139,3 +139,42 @@ class TestDetermineXInitiator:
 
     def test_empty_list_returns_user(self):
         assert determine_x_initiator([]) == "user"
+
+    def test_non_dict_items_ignored(self):
+        """Non-dict items in the list should be skipped."""
+        assert determine_x_initiator(["hello", 42, None]) == "user"
+
+    def test_system_plus_user_returns_user(self):
+        """System + user is still user-initiated."""
+        messages = [
+            {"role": "system", "content": "You are helpful"},
+            {"role": "user", "content": "Hi"},
+        ]
+        assert determine_x_initiator(messages) == "user"
+
+
+class TestGetCopilotDefaultHeaders:
+    """Tests for get_copilot_default_headers in common_utils.py."""
+
+    def test_basic_headers_without_conversation_key(self):
+        headers = get_copilot_default_headers(api_key="test-key-123")
+
+        assert headers["Authorization"] == "Bearer test-key-123"
+        assert headers["content-type"] == "application/json"
+        assert headers["copilot-integration-id"] == "vscode-chat"
+        assert "x-request-id" in headers
+        assert COPILOT_CONVERSATION_ID_HEADER not in headers
+
+    def test_headers_with_conversation_key(self):
+        headers = get_copilot_default_headers(
+            api_key="test-key", conversation_key="my-conv"
+        )
+
+        assert COPILOT_CONVERSATION_ID_HEADER in headers
+        conv_id = headers[COPILOT_CONVERSATION_ID_HEADER]
+        assert len(conv_id) == 36  # UUID format
+
+    def test_same_conversation_key_returns_same_id(self):
+        h1 = get_copilot_default_headers(api_key="k", conversation_key="stable-key")
+        h2 = get_copilot_default_headers(api_key="k", conversation_key="stable-key")
+        assert h1[COPILOT_CONVERSATION_ID_HEADER] == h2[COPILOT_CONVERSATION_ID_HEADER]