HYPERFLEET-1181 - docs: add test placement strategy

[kuudori]

Summary

• HYPERFLEET-1181

Test Plan

• Unit tests added/updated
• make test-all passes
• make lint passes
• Helm chart changes validated with make test-helm (if applicable)
• Deployed to a development cluster and verified (if Helm/config changes)
• E2E tests passed (if cross-component or major changes)

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Central YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Enterprise

Run ID: 898a3e34-7975-445f-be78-0217a6ebd9bd

📥 Commits

Reviewing files that changed from the base of the PR and between 0d41fa6 and dc5c5ec.

📒 Files selected for processing (1)

• hyperfleet/docs/e2e-testing/test-placement-strategy.md

🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

• openshift-hyperfleet/architecture (manual)
• openshift-hyperfleet/hyperfleet-api (manual)
• openshift-hyperfleet/hyperfleet-sentinel (manual)
• openshift-hyperfleet/hyperfleet-adapter (manual)
• openshift-hyperfleet/hyperfleet-broker (manual)

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📝 Walkthrough

Summary by CodeRabbit

• Documentation
  • Added a comprehensive "Test Placement Strategy" guide defining Unit, Integration, and E2E responsibilities with examples mapping assertions to the appropriate test layer.
  • Clarified overlap vs redundancy rules, when to remove higher-layer tests, and included a decision checklist for test placement.
  • Introduced a Coverage Durability policy requiring CI gating and review controls for test deletion, plus basic metadata (status, owner, last updated).

Walkthrough

This PR adds comprehensive documentation defining HyperFleet's test placement strategy across unit, integration, and E2E layers. It establishes explicit rules for selecting the lowest layer that can catch a given failure mode (validation, DB/serialization, or multi-component behavior), clarifies scope boundaries for each layer, distinguishes intentional overlap from redundancy, provides a step-by-step checklist for new tests, and introduces governance requirements including CI gating via required status checks, CODEOWNERS coverage, and constraints on test deletion/migration to prevent coverage gaps.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 11

✅ Passed checks (11 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly and accurately describes the main change: adding documentation for a test placement strategy.
Description check	✅ Passed	The description references the Jira ticket and indicates documentation is being added, which aligns with the changeset adding test placement strategy documentation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Sec-02: Secrets In Log Output	✅ Passed	PR adds only documentation (markdown file) to a documentation-only repository with no code files. No log statements or exposed secrets present.
No Hardcoded Secrets	✅ Passed	Documentation file contains no hardcoded secrets, API keys, tokens, passwords, or sensitive assignments. References to security concepts are documentation examples only.
No Weak Cryptography	✅ Passed	Documentation file contains no cryptographic code, no code examples with banned primitives (MD5, DES, RC4, SHA1, ECB), and no insecure comparison implementations. No weak cryptography usage present.
No Injection Vectors	✅ Passed	File is pure Markdown documentation with no executable code, code blocks, or injection patterns. CWE-89, CWE-78, CWE-79, CWE-502 checks not applicable to documentation.
No Privileged Containers	✅ Passed	No privileged containers detected. All container security contexts use non-root users and disable privilege escalation.
No Pii Or Sensitive Data In Logs	✅ Passed	Pure documentation file with no logging statements, code blocks, or PII/sensitive data exposure. Check not applicable to markdown documentation.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

✨ Simplify code

• Create PR with simplified code

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[openshift-ci]

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