feat: add shared utilities for e2e tests

Add common test infrastructure that both cluster and envtest modes will
use. This includes helper functions for running kubectl commands and
comparing JSON outputs, a provider registry that maps test directories
to their provider types, resource cleanup logic that respects Kubernetes
finalizers, and centralized timeout constants so all tests behave
consistently.

Author: nikatza

.license-scan-overrides.jsonl

@@ -1,6 +1,7 @@
 {"name": "github.com/chzyer/logex", "licenceType": "MIT"}
 {"name": "github.com/grpc-ecosystem/go-grpc-middleware/v2", "licenceType": "Apache-2.0"}
 {"name": "github.com/hashicorp/vault/api/auth/approle", "licenceType": "MPL-2.0"}
+{"name": "github.com/ironcore-dev/gnmi-test-server", "licenceType": "Apache-2.0"}
 {"name": "github.com/jpillora/longestcommon", "licenceType": "MIT"}
 {"name": "github.com/logrusorgru/aurora", "licenceType": "Unlicense"}
 {"name": "github.com/mattn/go-localereader", "licenceType": "MIT"}

test/e2e/testutil/doc.go

@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and IronCore contributors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package testutil provides test infrastructure for e2e tests.
+//
+// It supports two test modes selected by build tags:
+//
+//   - Envtest (build tag: envtest): Uses controller-runtime's envtest.Environment
+//     with an in-process gNMI test server. Fast (~10s) but doesn't test deployment.
+//
+//   - Cluster (default): Uses a real Kubernetes cluster (typically Kind) with a
+//     deployed operator and gnmi-test-server pod. Slower (~2-5min) but tests full stack.
+//
+// The concrete types ClusterEnvironment and EnvtestEnvironment provide the same
+// methods, allowing test logic to work with either mode via build tag selection.
+package testutil