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¶

Marker	Description
`unit`	Fast, isolated, no external dependencies
`integration`	Multiple components working together
`container`	Requires Docker/Podman containers
`slow`	Long-running tests (>5 seconds)
`postgres`	Requires PostgreSQL container
`redis`	Requires Redis container
`langfuse`	Requires Langfuse container
`prometheus`	Requires Prometheus container
`property`	Property-based tests using Hypothesis

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¶

Fixture	Description	Required Extra
`postgres_container`	PostgreSQL 15 Alpine	`testcontainers[postgres]`
`redis_container`	Redis 7 Alpine	`testcontainers`
`langfuse_container`	Langfuse 2 with PostgreSQL	`testcontainers[postgres]`
`prometheus_container`	Prometheus v2.47	`testcontainers`
`math_provider_container`	MCP Math Provider	Local image required
`sqlite_provider_container`	MCP SQLite Provider	Local image required

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(
    provider_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(provider_name, tool_name):
    """Adapter accepts any valid string inputs."""
    adapter = NullObservabilityAdapter()
    span = adapter.start_tool_span(provider_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 Provider¶

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

python -m mcp_hangar.server

Test via Python¶

from mcp_hangar.provider_manager import ProviderManager
from mcp_hangar.models import ProviderSpec

spec = ProviderSpec(
    provider_id="test",
    mode="subprocess",
    command=["python", "tests/mock_provider.py"]
)

mgr = ProviderManager(spec)
mgr.ensure_ready()

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

mgr.shutdown()

Test Provider Directly¶

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

Common Issues¶

Provider won't start¶

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

Permission denied (container)¶

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

Tests hang¶

pytest tests/ -v --timeout=60