migrator: tolerate context.Canceled in consumer group test stream goroutine

[mmatczuk]

Commits

• tolerate context.Canceled in consumer group test stream goroutine

Jira

• CON-446

[claude]

Commits
LGTM

Review
Single-file change that replaces require.NoError(t, stream.Run(ctx)) with the documented pattern of tolerating context.Canceled and using t.Errorf from a background goroutine. Matches the async-operations guidance in the project test patterns (see integration_test.go#L420-L426).

LGTM

[Jeffail]

Approving — correct narrow fix. context.Canceled is genuinely expected here: the goroutine's deferred cancel() races stream.StopWithin on shutdown and either ordering is benign. The require.NoError → t.Errorf swap also fixes the latent FailNow-from-non-test-goroutine bug per the testing package contract. Matches the dominant repo idiom.

Worth a follow-up (out of scope for this PR): the RunStreamInBackground helper at internal/impl/snowflake/integration_test.go:143 already implements this exact pattern (cleanup-driven cancel + wg.Wait + Canceled tolerance + non-FailNow assertion). Promoting it to a shared test helper would let us migrate the remaining require.NoError(t, stream.Run(...))-in-goroutine call sites across this file (e.g. L633, L688, L789, L901) and the sibling packages in one sweep instead of landing per-call-site one-line PRs.