Fix more tests

Author: vblagoje

integrations/mcp/tests/mcp_memory_transport.py

@@ -5,7 +5,7 @@
 from mcp.server import Server
 from mcp.shared.memory import create_connected_server_and_client_session
 
-from haystack_integrations.tools.mcp import MCPClient, MCPServerInfo
+from haystack_integrations.tools.mcp import MCPClient, MCPInvocationError, MCPServerInfo
 
 
 class InMemoryClient(MCPClient):
@@ -44,7 +44,12 @@ async def call_tool(self, tool_name: str, tool_args: dict[str, Any]) -> Any:
         async with create_connected_server_and_client_session(self.server) as session:
             await session.initialize()
             response = await session.call_tool(tool_name, tool_args)
-            return self._validate_response(tool_name, response)
+            if response.isError:
+                raise MCPInvocationError(
+                    message=f"Tool '{tool_name}' returned an error: {response.content!s}",
+                    tool_name=tool_name,
+                )
+            return response.model_dump_json()
 
 
 @dataclass

integrations/mcp/tests/test_mcp_tool.py

@@ -66,15 +66,15 @@ def test_mcp_tool_invoke(self, mcp_add_tool, mcp_echo_tool):
         """Test invoking MCPTools connected to in-memory servers."""
         # Test add tool invocation
         add_result = mcp_add_tool.invoke(a=25, b=17)
-        assert not add_result.isError
-        assert len(add_result.content) == 1
-        assert add_result.content[0].text == "42"  # 25 + 17
+        import json
+
+        add_result = json.loads(add_result)
+        assert add_result["content"][0]["text"] == "42"
 
         # Test echo tool invocation
         echo_result = mcp_echo_tool.invoke(text="Hello MCP!")
-        assert not echo_result.isError
-        assert len(echo_result.content) == 1
-        assert echo_result.content[0].text == "Hello MCP!"
+        echo_result = json.loads(echo_result)
+        assert echo_result["content"][0]["text"] == "Hello MCP!"
 
     def test_mcp_tool_error_handling(self, mcp_error_tool):
         """Test error handling with the in-memory server."""