egress-proxies-operator/docs/testing.md

Testing

What tests exist, how to run them, and where the boundaries of the automated suites are. The philosophy throughout: test against the most real double available — a real envtest API server over a fake client, a real CONNECT-capable proxy stub over a mocked HTTP client, the real lease store under the discovery handlers — and leave the gaps that only real infrastructure can close to the kind verification run, documented at the bottom.

Running

make test              # THE canonical run: codegen + fmt + vet + envtest setup,
                       # then `go test -race` on every package, with coverage
go test -short ./...   # skip the envtest suite (runs in <1s per package)
go tool cover -html=cover.out   # browse coverage from the last make test

Targeted runs:

go test -race ./internal/lease/                  # one package
go test -race -run TestAcquire ./internal/lease/ # one test (or a prefix)
go test -race -count=2 ./internal/health/        # flake-shaking: run twice

Gotcha — plain go test ./... fails the controller package with an error like /usr/local/kubebuilder/bin/etcd: no such file. That is not a code problem: the envtest suite needs KUBEBUILDER_ASSETS pointing at the API-server/etcd binaries, which only make test sets up (via setup-envtest). Either use make test, or export it once:

KUBEBUILDER_ASSETS="$PWD/bin/k8s/<version>-<os>-<arch>" go test -race ./...

Everything runs with -race — make test enforces it; keep the flag on manual runs too.

The suites, package by package

Package	Files	What is covered	Test double / technique
api/v1alpha1	helpers_test.go	EffectivePort/EffectiveHost/HealthCheckOrDefault/MaxLeasesOrDefault	pure table-driven; CEL rules are not unit-testable — see envtest below
internal/controller	reconcile_test.go	every row of the reconciler's action table: create, poll, publish IP, replace, adopt, NotFound recovery, delete/finalizer, quota/permanent/transient errors, cloud-init resolution	controller-runtime/pkg/client/fake + an in-test stubProvider
	status_test.go	computePhase truth table (10 rows)	pure
	spechash_test.go	hash stability, nil/empty normalization, sensitivity to every replacement-triggering field	pure
	health_test.go	Healthy-condition representation: Ready/Unhealthy phases, no-verdict, stale-verdict cleanup on replacement, nil snapshotter	fake client + fakeSnapshotter
	proxy_controller_test.go (envtest, ginkgo)	full lifecycles against a real API server: provision→Running, spec-change replacement, finalizer deletion, External tracking, Ready-through-health, quota-vs-permanent, adoption; all CEL rules (six invalid creates, mode/provider immutability incl. removal) and the default={} materialization	envtest apiserver + stub provider; the only place CEL and structural defaulting actually execute
internal/provider	name_test.go	deterministic naming: idempotency, ^proxy-[a-z2-7]{16}$, 10k-UID distinctness	pure
	errors_test.go	taxonomy: Class() mapping, errors.Is and errors.As through the multi-unwrap	pure
	config_test.go	providers-config parsing + fail-fast validation	pure
	metrics_test.go	WithMetrics decorator: classified result labels, error passthrough	fake recorder + static provider
internal/provider/kubernetes	kubernetes_test.go, pod_test.go	Create/Get/Delete/ListByTag over real Pod objects; pure buildPod/squidConf incl. the max_filedescriptors OOM-regression assertion	client/fake (real corev1.Pods, no kubelet)
internal/provider/gcp	insert_test.go, errors_test.go, gcp_test.go	field-by-field buildInsertRequest; HTTP-code classification table; zone-qualified IDs, 409-is-success, 9-row state mapping, ListByTag filter + ReturnPartialSuccess	pure builder needs no fake; the rest uses the flattened instancesAPI seam
internal/health	probe_test.go	probes through a real CONNECT-capable proxy stub to a real TLS server: tunnel success, refused CONNECT, wrong status, dead proxy, plain-http forward	httptest + hijacked bidirectional tunnel
	engine_test.go	thresholds, first-verdict, latency suppression matrix, dropped-event retry, stale-probe UID guard, tick scheduling/seeding/pruning, Start end-to-end	fake client.Reader + injected probeFn
internal/lease	store_test.go	capacity, MaxLeases=0, all three selection tie-breaks, target-scoped vs global cooldowns, expiry via fake clock, report-on-retained-lease, idempotent release, 40 concurrent acquires never exceeding capacity	injectable clock; the concurrency case is why -race matters
internal/discovery	server_test.go	auth matrix (incl. /healthz exemption), list filtering, grant shape, full 409 arithmetic, invalid TTL/body/result, idempotent release, report→cooldown→409 round trip, Start/shutdown	httptest over the real handler chain, fake cache reader, real lease.Store
internal/gc	gc_test.go	the true-orphan matrix (live/deleting/young/unlabelled all kept), broken-provider isolation, list-failure skips sweep, namespace guard, sweep loop	fake reader + canned-list provider
internal/metrics	metrics_test.go	scrape-time collectors (GatherAndCompare), per-proxy series cleanup via ForgetProxy, label counts, fresh-registry-per-test property	prometheus/client_golang/testutil

Conventions (from CLAUDE.md): stdlib testing, table-driven by default, t.Parallel() where safe, tests next to source, ginkgo only in the envtest suite the scaffold generated.

What the automated suites deliberately do NOT cover

• New() constructors that dial real infrastructure: the kubernetes provider's New (connects to whatever your kubeconfig points at), the GCP provider's New and its realInstances SDK adapter (ADC + real Google endpoints). Both are thin; both are exercised by the kind run / real deployments. Their 0% coverage is by design — do not "fix" it.
• CEL and structural defaulting under the fake client: the fake client runs neither. Every unit test that relies on defaults calls the *OrDefault helpers; every CEL rule is asserted in the envtest suite instead.
• A container actually starting and serving: envtest has no kubelet, so a Pod created there sits Pending forever. Whether Squid really comes up and tunnels CONNECT is provable only on a real cluster — that is the kind verification's job, and it is exactly what caught the Squid OOM bug (below).
• Live GCP: no test talks to Google. The seam boundary (buildInsertRequest + classification) is tested exhaustively instead.

The scaffolded make test-e2e suite

test/e2e/ is the kubebuilder-generated smoke suite (build image → kind cluster → deploy → assert the manager pod runs and serves metrics). It compiles only under -tags=e2e, manages its own kind cluster (make test-e2e / make cleanup-test-e2e), and has been kept compiling (go vet -tags=e2e ./... is part of the routine) but is not part of make test and was not used for the release verification — the manual kind run below covers strictly more. Treat it as scaffold to grow into if CI wants an automated cluster smoke test.

The kind verification run (the real end-to-end)

The README quickstart is the e2e test, run by hand before the MR: deploy the operator in-cluster on a throwaway kind cluster, watch a real Squid pod reach Ready via a real CONNECT probe, then exercise the whole lease lifecycle through the discovery API (list → lease → report rate_limited → same-target lease answered 409 inCooldown:1 → release 204 twice) and delete the CR to watch the finalizer remove the pod.

Worth knowing about that run (full detail in plans-executions/2026-08-07-1747-proxy-operator.md, "Verification" section): it was not a clean pass-through. It caught two real bugs the automated suites structurally could not —

1. make run-dev on a laptop can never produce a Ready kubernetes-provider proxy: health probes originate on the host, which cannot route to kind's pod network. The quickstart was rewritten to deploy in-cluster.
2. Squid was OOM-killed at startup: it sizes file-descriptor tables from RLIMIT_NOFILE, which containerd under kind sets effectively unlimited. Fixed with max_filedescriptors 1024 in the generated config, plus a regression assertion in pod_test.go.

That is the pattern to keep: when the kind run finds something, the fix lands with a unit-level regression test, so the manual run stays a discovery tool rather than a recurring gate.