Testing

Quick Start

uv sync --extra dev
uv run pytest tests/ -v -m "not slow"

Running Tests

# All unit tests
pytest tests/unit/ -v

# By marker
pytest tests/ -m unit
pytest tests/ -m integration
pytest tests/ -m "not container"

# Coverage
pytest tests/ -m "not slow" --cov=mcp_hangar --cov-report=html

Markers

Testcontainers Integration

MCP Hangar uses Testcontainers for integration tests with real services.

Installation

pip install mcp-hangar[testcontainers]
# or
pip install "testcontainers[postgres]>=4.0.0" httpx

Running Container Tests

# Run all container tests (requires Docker/Podman)
pytest tests/integration/containers/ --run-containers -v

# Run specific container tests
pytest tests/integration/containers/test_postgres.py --run-containers -v
pytest tests/integration/containers/test_langfuse.py --run-containers -v
pytest tests/integration/containers/test_redis.py --run-containers -v

# Skip slow container tests
pytest tests/integration/containers/ --run-containers -m "not slow" -v

Available Container Fixtures

Example: Using PostgreSQL Container

import pytest

@pytest.mark.container
@pytest.mark.postgres
def test_database_operations(postgres_container):
    """Test with real PostgreSQL database."""
    dsn = postgres_container["dsn"]

    import asyncpg
    conn = await asyncpg.connect(dsn)
    result = await conn.fetchval("SELECT 1")
    assert result == 1

Example: Using Langfuse Container

import pytest

@pytest.mark.container
@pytest.mark.langfuse
def test_langfuse_tracing(langfuse_config, langfuse_container, http_client):
    """Test with real Langfuse instance."""
    from mcp_hangar.infrastructure.observability.langfuse_adapter import (
        LangfuseObservabilityAdapter,
    )

    adapter = LangfuseObservabilityAdapter(langfuse_config)
    span = adapter.start_tool_span("test", "tool", {"arg": 1})
    span.end_success({"result": "ok"})
    adapter.flush()

    # Query Langfuse API
    response = http_client.get(
        f"{langfuse_container['url']}/api/public/traces",
        auth=(langfuse_container["public_key"], langfuse_container["secret_key"]),
    )
    assert response.status_code == 200

Property-Based Testing

MCP Hangar uses Hypothesis for property-based testing.

Running Property Tests

# All property tests
pytest tests/unit/observability/test_property_based.py -v

# With more examples
pytest tests/unit/observability/test_property_based.py -v --hypothesis-seed=12345

Example Property Test

from hypothesis import given, strategies as st

@given(
    mcp_server_name=st.text(min_size=1, max_size=50),
    tool_name=st.text(min_size=1, max_size=50),
)
def test_adapter_accepts_any_strings(mcp_server_name, tool_name):
    """Adapter accepts any valid string inputs."""
    adapter = NullObservabilityAdapter()
    span = adapter.start_tool_span(mcp_server_name, tool_name, {})
    assert isinstance(span, NullSpanHandle)

Container Tests

# Build images first
podman build -t localhost/mcp-sqlite -f docker/Dockerfile.sqlite .

# Prepare data directory
mkdir -p data && chmod 777 data

# Run tests
pytest tests/feature/ -v

Manual Testing

Subprocess MCP Server

# config.yaml
mcp_servers:
  math:
    mode: subprocess
    command: [python, tests/mock_mcp_server.py]

python -m mcp_hangar.server

Test via Python

from mcp_hangar.domain.model import McpServer

mcp_server = McpServer(
    mcp_server_id="test",
    mode="subprocess",
    command=["python", "tests/mock_mcp_server.py"]
)

mcp_server.ensure_ready()

result = mcp_server.invoke_tool("add", {"a": 5, "b": 3})
print(result)  # {"result": 8}

mcp_server.shutdown()

Test MCP Server Directly

echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}' | python tests/mock_mcp_server.py

Common Issues

MCP Server won't start

# Test directly
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}' | python tests/mock_mcp_server.py

Permission denied (container)

mcp_servers:
  memory:
    mode: container
    read_only: false
    volumes:
      - "./data:/app/data:rw"

Tests hang

pytest tests/ -v --timeout=60