Separate mock golden files from real GCP files in script_test.go #13478

Problem Statement

In tests/e2e/script_test.go (which runs multi-step scenario tests under tests/e2e/testdata/scenarios/), golden file paths are currently hardcoded with identical names for both real GCP and Mock GCP runs:

• HTTP Logs: _http%02d.log
• KRM Objects: _object%02d.yaml
• Exported Objects: _export%d.yaml

When scenario tests are run against Mock GCP (E2E_GCP_TARGET=mock) with WRITE_GOLDEN_OUTPUT=1, mock outputs overwrite the real GCP ground-truth golden files.

Impact

1. Loss of Ground Truth: Mock reconciliation overwrites authentic GCP logs and object states with simulated mock data.
2. Inconsistency with Basic Fixtures: In tests/e2e/unified_test.go, basic test fixtures cleanly separate real outputs (_http.log, _generated_object_*.golden.yaml) from mock outputs (_http_mock.log, _http_mock.diff). script_test.go should adhere to the same pattern.
3. Blocks Automated Parity Verification: Automated alignment testing (pkg/test/goldenalignment) cannot compare multi-step scenario logs and KRM object states side-by-side unless both real and mock files coexist.

Proposed Solution

1. Target-Aware Filenames in tests/e2e/script_test.go:
   Determine golden file paths dynamically based on E2E_GCP_TARGET:

   • Real GCP (E2E_GCP_TARGET=real):
     • _http%02d.log
     • _object%02d.yaml
     • _export%d.yaml
   • Mock GCP (E2E_GCP_TARGET=mock):
     • _http%02d_mock.log
     • _object%02d_mock.yaml
     • _export%d_mock.yaml

2. Writing & Comparison Logic:

   • When WRITE_GOLDEN_OUTPUT=1 is set during a mock run, write the step outputs to the *_mock.* files.
   • When running mock assertions, compare against the appropriate golden target files.

Acceptance Criteria

• Running scenario tests with E2E_GCP_TARGET=real WRITE_GOLDEN_OUTPUT=1 records _http%02d.log and _object%02d.yaml.
• Running scenario tests with E2E_GCP_TARGET=mock WRITE_GOLDEN_OUTPUT=1 records _http%02d_mock.log and _object%02d_mock.yaml.
• Mock test runs do not overwrite real GCP golden baseline files in tests/e2e/testdata/scenarios/.
• Generate and check in *_mock.* golden files for all scenario tests covered by presubmit suites (dev/ci/presubmits/tests-scenarios-suite).