refactor(e2e): use error-returning assertions

[r2k1]

What this PR does / why we need it:

• Adds a generic e2e/assert package that returns structured errors without depending on testing.T.
• Propagates assertion and operational errors through E2E validators and helpers to test boundaries.
• Keeps Testify in unit tests and preserves existing logging, cleanup, PIS lifecycle, and named CSE timing subtests.

Which issue(s) this PR fixes:

N/A

[github-actions]

Windows Unit Test Results

  3 files   12 suites   51s ⏱️
389 tests 389 ✅ 0 💤 0 ❌
392 runs  392 ✅ 0 💤 0 ❌

Results for commit fb147b9.

♻️ This comment has been updated with latest results.

[Copilot]

Pull request overview

This PR refactors the E2E test harness to replace testify/require/assert-style test-bound assertions with a new e2e/assert package that returns structured errors, enabling validators/helpers to propagate failures to the test boundary while still running independent checks and preserving existing diagnostics/cleanup behavior.

Changes:

• Introduces e2e/assert (and unit tests) providing error-returning assertions in (got, want) order.
• Converts multiple E2E validators/helpers to return error (often aggregating via errors.Join) and updates scenario/test plumbing to handle propagated errors.
• Updates VM/VMSS provisioning, execution helpers, and timing validation to return errors instead of calling Fatal/Fatalf, while keeping existing logging/diagnostic collection patterns.

Reviewed changes

Copilot reviewed 19 out of 21 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
e2e/vmss.go	Refactors VMSS model creation and custom data mutation to return errors; updates VMSS creation flow to use error-returning helpers.
e2e/validators_kata.go	Converts Kata validators to return aggregated errors and use e2e/assert.
e2e/validation.go	Converts common validation orchestration and several helpers to return error and aggregate independent failures.
e2e/validate_localdns_exporter_metrics.go	Converts exporter metrics validation to error-returning flow and e2e/assert.
e2e/types.go	Extends scenario config with *WithError mutators and changes Validator signature to func(...) error.
e2e/test_helpers.go	Updates scenario runner/pre-provision flow to propagate errors instead of require.*/Fatalf.
e2e/scenario_win_test.go	Updates Windows scenario validators/mutators to return errors and aggregate checks.
e2e/scenario_rcv1p_win_test.go	Updates RCV1P Windows tests to handle error-returning mutator construction and validators.
e2e/scenario_rcv1p_test.go	Refactors feature-flag/CSE zip helper flows to return errors (skip vs fail) and reduce hard test-bound failures.
e2e/scenario_gpu_managed_experience_test.go	Adds helper validators for version pin checks and refactors GPU scenarios to error-returning/ordered validation.
e2e/scenario_gpu_daemonset_test.go	Converts daemonset deployment/wait and validations to return errors and use e2e/assert.
e2e/scenario_cse_perf_test.go	Updates perf tests to consume ValidateCSETimings’ new (report, error) signature.
e2e/node_config.go	Refactors base NBC/template creation to return errors and adds runtime completeness checks.
e2e/kube.go	Converts WaitUntilNodeReady to return (string, error) instead of failing the test directly.
e2e/exec.go	Refactors VM/pod exec helpers to return errors; improves error handling (e.g., rand.Read) and nil safety.
e2e/cse_timing.go	Changes timing validation to return (report, error) while still emitting per-threshold subtests.
e2e/assert/assert.go	New error-returning assertion utilities with structured field formatting and wrapped causes.
e2e/assert/assert_test.go	Unit tests for the new e2e/assert package’s formatting and behavior.
e2e/artifact_streaming.go	Converts artifact streaming validation and supporting helpers to error-returning flow with preserved diagnostics.

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[Copilot]

Pull request overview

Copilot reviewed 19 out of 21 changed files in this pull request and generated no new comments.

Suppressed comments (2)

e2e/vmss.go:335

• When addPodIPConfigsForAzureCNI fails, the error is returned without context. Wrapping it will make it clearer which step failed when VMSS creation errors bubble up.

		if err != nil {
			return armcompute.VirtualMachineScaleSet{}, err
		}

e2e/vmss.go:223

• The nil-guard in createVMSSModel returns a generic error message, which makes it hard to debug which required Scenario field is missing. Including the key required fields in the message would make failures actionable without needing extra logs.

This issue also appears on line 333 of the same file.

		return armcompute.VirtualMachineScaleSet{}, fmt.Errorf("scenario runtime is incomplete for VMSS model creation")

[Copilot]

Pull request overview

Copilot reviewed 19 out of 21 changed files in this pull request and generated no new comments.

Suppressed comments (3)

e2e/test_helpers.go:94

• RunScenario calls s.T.Error(err) when runScenario returns an error, but s.T is assigned inside runScenario; if runScenario fails before setting it, this will panic. Report the error on the current test handle (t) instead.

	if config.Config.DisableScriptless || scriptlessUnsupported(s) {
		if err := runScenario(t, s); err != nil {
			s.T.Error(err)
		}
		return

e2e/test_helpers.go:103

• Same issue as above: s.T may be nil when handling errors from runScenario. Using t.Error(err) avoids a nil dereference and ensures the failure is attributed to the correct test/subtest.

	if s.Runtime == nil {
		s.Runtime = &ScenarioRuntime{}
	}
	s.Runtime.EnableScriptlessNBCCSECmd = true
	if err := runScenario(t, s); err != nil {
		s.T.Error(err)
	}

e2e/test_helpers.go:86

• RunScenario reports errors via s.T.Error(err), but s.T is not initialized until inside runScenario (and in the VHDCreation subtest it may remain nil on early failure), which can panic and hide the real error. Use the local *testing.T (the subtest's t) to report the failure instead.

This issue also appears in the following locations of the same file:

• line 90
• line 97

		t.Run("VHDCreation", func(t *testing.T) {
			t.Parallel()
			if err := runScenarioWithPreProvision(t, s); err != nil {
				s.T.Error(err)
			}