test: lifecycle/error-path coverage + teardown determinism (#68)

[senolcolak]

Closes #68. Fixes #78. Stacked on #80 (#66) → #79 (#67).

What

Adds fast, pure-unit coverage for the safety-critical reconciler branches that were previously reachable only through the slow envtest suite, fixes the teardown race that forced RandomizeAllSpecs off (#78), and corrects three webhook validation bugs that the new tests surfaced.

Coverage (#68)

• Extract pure helpers allocateMonID and determinePublicAddressFor from the reconciler methods; the methods now delegate to these free functions (behavior-preserving — reviewed branch-by-branch). Unit-tested in pkg/controller/allocation_test.go (no build tag, no API server):
  • mon-ID: first-free, single/run collision skip, other-prefix isolation, last-suffix, a–z exhaustion error.
  • public address: nil-service pod-IP substitution, ClusterIP allocated/unallocated, NodePort, LoadBalancer IPv4 / skip-bad-then-IPv4 / no-ingress / IPv6-only, unknown type.
• docs/testing/traceability.md: maps each reconcile transition and error branch to its covering spec, marking honest gaps for the deferred deletion-cascade and observedGeneration work (tracked follow-up).
• Makefile: run ./pkg/controller/... in the unit layer (untagged pure tests), and add a report-only test-cover target merging unit + envtest coverage profiles (COVER_MIN gates once a floor is measured).

Teardown determinism (#78)

• namespaceCleanUp force-strips finalizers tolerating both NotFound and Conflict, re-listing fresh each pass, converging inside a single Eventually that requires source and target namespaces empty in the same pass (source first, so the deleted RemoteArbiter stops repopulating the target).
• Re-enable RandomizeAllSpecs. The "should succeed" spec waits 2 min: the reconciler has no watch on the target Deployment and only re-observes via the 1-min CheckInterval requeue, so the shared 30s timeout was intrinsically racy — this fixes the root cause, not the symptom.

Webhook fixes (regression-guarded)

Three field.Invalid calls reported the wrong value as BadValue, producing misleading admission errors:

• cephCluster.namespace reported .Name; monIdPrefix reported remoteCluster.Name.
• The NodePort nodeIp branch reported Service.Type and, on an unparseable IP, fell through to the Is4() check and appended a second spurious error. Fixed to one error naming the NodeIP.

Guarded by TestValidateRemoteArbiterSpecErrorBadValue and TestValidateRemoteArbiterSpecNodeIPErrorBadValue — both proven to fail on the pre-fix code and pass after.

Verification

gofmt clean · go vet ./... and -tags envtest clean · make test-unit green · golangci-lint 0 issues · envtest suite green (5× with shuffle) · make gen/helm/imports no-op.

[jrse]

LGTM