arcade-mcp/libs/tests/sdk/test_errors.py
jottakka 98fad93d21
Adding MCP Servers supports to Arcade Evals (#689)
# MCP Server Tool Evaluation Support

## Overview
Add support for evaluating tools from remote MCP servers without
requiring Python callables. Enables direct evaluation of any
MCP-compatible tool server.

## What's New

### Core Features
- **`MCPToolRegistry`**: Evaluate tools from a single MCP server
- **`CompositeMCPRegistry`**: Evaluate tools from multiple MCP servers
simultaneously
- **Automatic loaders**: `load_from_stdio()` and `load_from_http()` to
fetch tools from running servers
- **Automatic namespacing**: Tools prefixed with server name (e.g.,
`server_tool_name`)
- **Smart name resolution**: Use short names if unique, full names if
ambiguous
- **OpenAI strict mode**: Automatic schema conversion prevents parameter
hallucinations

### Usage

**Automatic Loading:**
```python
from arcade_evals import load_from_stdio, MCPToolRegistry

# Load tools automatically from MCP server
tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-github"])
registry = MCPToolRegistry(tools)
```

**Single MCP Server:**
```python
from arcade_evals import MCPToolRegistry, ExpectedToolCall

registry = MCPToolRegistry(mcp_tools)
suite = EvalSuite(catalog=registry)

suite.add_case(
    expected_tool_calls=[
        ExpectedToolCall(tool_name="tool_name", args={...})
    ]
)
```

**Multiple MCP Servers:**
```python
from arcade_evals import CompositeMCPRegistry, load_from_stdio

# Load from multiple servers
github_tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-github"])
slack_tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-slack"])

composite = CompositeMCPRegistry(
    tool_lists={
        "github": github_tools,
        "slack": slack_tools,
    }
)

suite = EvalSuite(catalog=composite)

suite.add_case(
    expected_tool_calls=[
        ExpectedToolCall(tool_name="github_list_issues", args={...})
    ]
)
```

## Implementation

### Files Changed
- **`libs/arcade-evals/arcade_evals/registry.py`** (NEW): Registry
abstractions and implementations
- **`libs/arcade-evals/arcade_evals/loaders.py`** (NEW): Automatic tool
loading from MCP servers
- **`libs/arcade-evals/arcade_evals/eval.py`** (MODIFIED): Enhanced
`ExpectedToolCall` and evaluation logic
- **`libs/arcade-evals/arcade_evals/__init__.py`** (MODIFIED): Exported
new registries and loaders

### Key Technical Details
- Added `BaseToolRegistry` interface for abstraction
- `MCPToolRegistry` handles single server tools
- `CompositeMCPRegistry` manages multiple servers with collision
detection
- `load_from_stdio()` and `load_from_http()` for automatic tool
discovery
- Fixed name normalization bug: MCP tools use underscores (not dots)
- Optimized tool copying: 2.5x faster via shallow copy

## Testing
-  41 tests passing (25 new tests added)
-  `test_eval_mcp_registry.py`: MCPToolRegistry functionality
-  `test_eval_composite_mcp.py`: CompositeMCPRegistry with multiple
servers
-  Verified backward compatibility with Python tools

## Backward Compatibility
 **100% backward compatible** - No breaking changes


## Breaking Changes
**None**


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds end-to-end eval UX: examples, a robust CLI runner, and rich
outputs.
> 
> - **New examples**: `eval_arcade_gateway.py`,
`eval_stdio_mcp_server.py`, `eval_http_mcp_server.py`,
`eval_comprehensive_comparison.py` with timeouts, error handling, and
track-based comparisons; detailed `README.md`
> - **CLI runner**: `arcade_cli/evals_runner.py` to execute
evals/capture in parallel with progress, error isolation, failed-only
filtering, context inclusion, and multi-provider/model support
> - **Output formatters**: `arcade_cli/formatters/` (txt, md, html,
json) for evals and capture; comparative and multi-model HTML with tabs
and context rendering
> - **Display refactor**: `display.py` now supports writing multiple
formats, failed-only disclaimers, include-context, and improved console
summaries
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
ff8acf9c34a6b61462a019a1ee9df081006517d0. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Francisco Liberal <francisco@arcade.dev>
Co-authored-by: Mateo Torres <torresmateo@gmail.com>
2026-01-07 20:26:23 -03:00

69 lines
2.4 KiB
Python

"""Tests for arcade_evals.errors module."""
import pytest
from arcade_evals.errors import EvalError, WeightError
class TestEvalError:
"""Tests for EvalError base class."""
def test_eval_error_is_exception(self) -> None:
"""Test that EvalError is an Exception subclass."""
assert issubclass(EvalError, Exception)
def test_eval_error_can_be_raised(self) -> None:
"""Test that EvalError can be raised and caught."""
with pytest.raises(EvalError) as exc_info:
raise EvalError("test error")
assert str(exc_info.value) == "test error"
def test_eval_error_with_no_message(self) -> None:
"""Test that EvalError can be raised without a message."""
with pytest.raises(EvalError):
raise EvalError()
class TestWeightError:
"""Tests for WeightError class."""
def test_weight_error_is_eval_error_subclass(self) -> None:
"""Test that WeightError is a subclass of EvalError."""
assert issubclass(WeightError, EvalError)
def test_weight_error_is_exception(self) -> None:
"""Test that WeightError is an Exception subclass."""
assert issubclass(WeightError, Exception)
def test_weight_error_can_be_raised(self) -> None:
"""Test that WeightError can be raised and caught."""
with pytest.raises(WeightError) as exc_info:
raise WeightError("invalid weight")
assert str(exc_info.value) == "invalid weight"
def test_weight_error_caught_as_eval_error(self) -> None:
"""Test that WeightError can be caught as EvalError."""
with pytest.raises(EvalError):
raise WeightError("weight constraint violated")
def test_weight_error_caught_as_exception(self) -> None:
"""Test that WeightError can be caught as generic Exception."""
with pytest.raises(Exception):
raise WeightError("test")
class TestErrorImports:
"""Tests for error class imports."""
def test_import_from_errors_module(self) -> None:
"""Test that errors can be imported from arcade_evals.errors."""
from arcade_evals.errors import EvalError, WeightError
assert EvalError is not None
assert WeightError is not None
def test_errors_in_module_all(self) -> None:
"""Test that errors are in __all__."""
from arcade_evals import errors
assert "EvalError" in errors.__all__
assert "WeightError" in errors.__all__