Summary

ClickHouseQueryActivityTool and ClickHouseSystemHealthTool have no unit tests. An integration test at tests/integrations/test_clickhouse.py covers config validation, but tool-level behaviour is untested.

Context

Both tools delegate to app/integrations/clickhouse.py (get_query_activity, get_system_health) and use a shared config model ClickHouseConfig plus clickhouse_is_available and clickhouse_extract_params helpers. The ClickHouse client (clickhouse_connect) is imported lazily — no live instance needed in tests.

What to implement

Create two files:

• tests/tools/test_clickhouse_query_activity_tool.py
• tests/tools/test_clickhouse_system_health_tool.py

Each should cover:

1. Contract test — inherit BaseToolContract from tests/tools/conftest.py
2. is_available — True when sources["clickhouse"] has host and connection_verified: True; False otherwise
3. extract_params — assert host, port, database, username, limit are mapped correctly from sources
4. run happy path — patch app.integrations.clickhouse.get_query_activity (or get_system_health) with a MagicMock and assert the tool returns available: True with the expected structure
5. run error path — patch to raise an exception (e.g., Exception("connection refused")) and verify a graceful error dict is returned

Acceptance criteria

• Two test files under tests/tools/
• Covers all scenarios above
• make test-cov passes
• make lint passes

References

• Pattern: tests/tools/test_elasticsearch_logs_tool.py (closest analogue — similar structure)
• Tool sources: app/tools/ClickHouseQueryActivityTool/, app/tools/ClickHouseSystemHealthTool/
• Integration helpers: app/integrations/clickhouse.py
• Existing integration test: tests/integrations/test_clickhouse.py