Why This Matters

the Mimir mixin builds PromQL queries and normalizes result series, but it is currently untested directly.

Read First

• app/services/grafana/mimir.py

Scope

1. Reuse the same fake-client style as in the Loki tests.
2. Test both plain metric queries and service-filtered queries.
3. Test the error envelope.

Tests / Coverage

• tests/services/test_grafana_mimir.py
• cover query-string construction
• cover result-series normalization
• cover not-configured and exception cases

Acceptance Criteria

• Mimir query construction is directly protected
• service filtering is tested
• no real network calls are required