Delivery groups have no acceptance-test coverage, and the metrics ATs encode two fixed bugs #397

Summary

Delivery groups — the headline feature of v2.6.0 — have no acceptance-test coverage at all. Separately, the metrics acceptance tests that do exist were written around two bugs, so they could never have caught them.

1. Delivery groups: zero coverage

grep -rn "delivery-group" test/acceptance/   # → 0 hits

Nothing in the AT suite passes --delivery-group-key, --delivery-group-rate, --delivery-group-rate-period or --delivery-group-overrides, in either the standalone (gateway destination) or inline (--destination-delivery-group-*) form.

What does exist is destination-level rate limiting (--destination-rate-limit, three cases in connection_test.go:1586-1682), which is pre-existing v2.5.0 functionality, not delivery groups.

Consequence: a green acceptance run on the release PR confirms the release did not break what v2.5.0 already did. It says nothing about the feature the release is being cut for. Every delivery-group bug found so far (#393, and the two fixed in #392) was found by hand, not by CI.

Suggested cases

• create a destination with a full group triple plus --delivery-group-overrides, read back, assert the stored delivery_policy
• bump the group rate via upsert and assert the overrides survived — the gateway upsert silently destroys delivery_policy.groups.overrides #393 regression guard, currently covered only by a unit test
• the same via connection create / connection upsert with the --destination-* prefixed forms
• --rate-limit/--delivery-group-* against --type CLI is rejected (the fix: delivery-group data loss and metrics defects, plus the missing acceptance coverage #392 fix)
• partial flag sets are rejected pre-flight and create nothing

2. The metrics ATs encode the bugs they should have caught

test/acceptance/metrics_test.go:

• TestMetricsEventsPending passes --measures pending --granularity 1h. Granularity was exactly the workaround for the routing bug fixed in fix: delivery-group data loss and metrics defects, plus the missing acceptance coverage #392 — without it the command returned a 422. The test asserts the broken behaviour's happy path.
• TestMetricsEventsQueueDepth uses --measures max_depth, never queue_depth — the value advertised in --help that could never succeed.

Both passed before and after the fix. Worth adding the cases that would have failed: --measures pending with no granularity, and --measures queue_depth.

Why this is worth doing rather than noting

The acceptance suite is the gate the release is judged on. Where it has no coverage the gate reports green, which reads as "verified" rather than "not tested" — the same silent-success shape as the bugs themselves.

Related

• gateway upsert silently destroys delivery_policy.groups.overrides #393 — the data loss the upsert case would guard
• fix: delivery-group data loss and metrics defects, plus the missing acceptance coverage #392 — the fixes whose AT coverage is missing
• Acceptance tests leak sources and destinations: ~36k of each in the CI Gateway project #362 — acceptance tests leaking resources (the same project shows ~100 orphaned test-dst-*)

Filed by Claude on Phil's behalf, from release-candidate testing.