test: KVStore, ServiceLauncher, and MetricsAggregator services lack integration tests

[arekay-nv]

Problem

Three new infrastructure services were added in late March 2026 with no integration test coverage:

• KVStore + ServiceLauncher + ready-check mechanism — added in commit fd7b4ed ("Add KVStore, ready-check mechanism, and ServiceLauncher")
• MetricsAggregator service — added in commit 08476d7 ("add metrics_aggregator service for real-time metric computation")

These are located under src/inference_endpoint/async_utils/services/. Issue #213 already shows a production failure (psycopg.errors.DuplicatePreparedStatement) originating from this layer, demonstrating that the lack of test coverage is causing real bugs.

Expected Behavior

Integration tests should cover:

• KVStore read/write lifecycle
• ServiceLauncher startup, ready-check, and teardown
• MetricsAggregator receiving events and computing metrics correctly
• PostgreSQL/psycopg interaction (the source of Resolve Endpoints PostGres dup element issue #213)

Related

• Resolve Endpoints PostGres dup element issue #213 — PostgreSQL DuplicatePreparedStatement bug in recorder (same service layer)

Files

• src/inference_endpoint/async_utils/services/
• tests/integration/ — new test files needed