Ensure openapi path params are handled properly

tests/server/test_openapi_array_params.py

@@ -0,0 +1,90 @@
+from unittest.mock import AsyncMock, MagicMock
+
+import httpx
+import pytest
+
+from fastmcp.server.openapi import OpenAPITool
+from fastmcp.utilities.openapi import HTTPRoute, ParameterInfo
+
+
+@pytest.fixture
+def mock_client():
+    """Create a mock httpx.AsyncClient."""
+    client = AsyncMock(spec=httpx.AsyncClient)
+    # Set up a mock response
+    mock_response = MagicMock()
+    mock_response.json.return_value = {"result": "success"}
+    mock_response.raise_for_status.return_value = None
+    client.request.return_value = mock_response
+    return client
+
+
+@pytest.mark.asyncio
+async def test_array_path_parameter_handling(mock_client):
+    """Test how array path parameters are handled."""
+    # Create a simple route with array path parameter
+    route = HTTPRoute(
+        path="/select/{days}",
+        method="PUT",
+        operation_id="test-operation",
+        parameters=[
+            ParameterInfo(
+                name="days",
+                location="path",
+                required=True,
+                schema={
+                    "type": "array",
+                    "items": {
+                        "type": "string",
+                        "enum": [
+                            "monday",
+                            "tuesday",
+                            "wednesday",
+                            "thursday",
+                            "friday",
+                            "saturday",
+                            "sunday",
+                        ],
+                    },
+                },
+            )
+        ],
+    )
+
+    # Create the tool
+    tool = OpenAPITool(
+        client=mock_client,
+        route=route,
+        name="test-operation",
+        description="Test operation",
+        parameters={},
+    )
+
+    # Test with a single value
+    await tool._execute_request(days=["monday"])
+
+    # Check that the path parameter is formatted correctly
+    # This is where the bug is: it should be '/select/monday' not '/select/[\'monday\']'
+    mock_client.request.assert_called_with(
+        method="PUT",
+        url="/select/monday",  # This is the expected format
+        params={},
+        headers={},
+        json=None,
+        timeout=None,
+    )
+    mock_client.request.reset_mock()
+
+    # Test with multiple values
+    await tool._execute_request(days=["monday", "tuesday"])
+
+    # Check that the path parameter is formatted correctly
+    # It should be '/select/monday,tuesday' not '/select/[\'monday\', \'tuesday\']'
+    mock_client.request.assert_called_with(
+        method="PUT",
+        url="/select/monday,tuesday",  # This is the expected format
+        params={},
+        headers={},
+        json=None,
+        timeout=None,
+    )