🧪 [testing improvement] Add missing username validation edge case tests

[is0692vs]

🎯 What: The isValidGitHubUsername function in src/lib/validators.ts was missing test coverage for several important edge cases, making the validation logic susceptible to regressions.
📊 Coverage: Added test cases for multibyte characters (Kanji, emojis), whitespace and control characters, purely hyphenated strings, and extremely long strings (to check for ReDoS).
✨ Result: Test coverage for isValidGitHubUsername is significantly improved, ensuring the regular expression robustness against invalid username patterns.

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PR created automatically by Jules for task 15745143920105382679 started by @is0692vs

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Project	Deployment	Actions	Updated (UTC)
github-user-summary	Ready	Preview, Comment	Mar 21, 2026 4:36am

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on bolstering the reliability and security of the isValidGitHubUsername function. By introducing comprehensive test cases for previously unaddressed edge scenarios, such as multibyte characters, whitespace, and potential ReDoS attack vectors, the changes ensure the validation logic is more resilient and less prone to regressions, ultimately enhancing the integrity of username handling.

Highlights

• Test Coverage Improvement: Enhanced the test suite for the isValidGitHubUsername function by adding new test cases for critical edge scenarios.
• Edge Case Validation: Introduced tests to validate multibyte characters (e.g., Japanese, emojis), whitespace, control characters, strings composed solely of hyphens, and extremely long strings to prevent ReDoS vulnerabilities.
• Regular Expression Robustness: Significantly improved the robustness of the username validation regular expression by ensuring it correctly handles various invalid patterns.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 9cb782bb-812d-41bc-9480-f44cf5fec6f5

📥 Commits

Reviewing files that changed from the base of the PR and between b711fdc and efd02a2.

📒 Files selected for processing (1)

• src/lib/__tests__/validators.test.ts

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📝 Walkthrough

Summary by CodeRabbit

リリースノート

• Tests
  • GitHubユーザー名検証の単体テストを拡充しました。マルチバイト文字（日本語・絵文字・アクセント付き文字）を含むケース、空白や改行・タブ・NULなどの制御文字を含むケース、極端に長い（長さ1000）入力の無効扱いを検証するテストを追加しました。

Walkthrough

isValidGitHubUsername のユニットテストを拡張し、非ASCII／マルチバイト文字、ホワイトスペース／制御文字（先頭末尾スペース、改行、タブ、NUL）、および長さ1000の文字列を含む無効ケースを追加しました。

Changes

Cohort / File(s)	Summary
Test Case Expansion src/lib/__tests__/validators.test.ts	isValidGitHubUsername に対し、非ASCII・マルチバイト文字（日本語、絵文字、アクセント文字）、ホワイトスペース・制御文字（先頭/末尾スペース、改行、タブ、NUL）、および長さ1000の長文字列を含む無効ケーステストを追加（+19 行）。

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 テスト増えたよ、ぴょんぴょんと
不正文字も、空白も、NULも蹴散らす
長い文字列もにっこり受け止め
バリデータ、堅く守るよ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	プルリクエストのタイトルは、主な変更内容（isValidGitHubUsername関数のテストカバレッジ拡大）を明確に説明しており、変更セットに完全に関連している。
Description check	✅ Passed	説明は、追加されたテストケース（マルチバイト文字、ホワイトスペース、制御文字、長い文字列）について詳しく述べており、変更セットに完全に関連している。
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/test-username-validators-15745143920105382679

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[gemini-code-assist]

Code Review

このプルリクエストでは、isValidGitHubUsername 関数のバリデーションロジックに対して、これまでカバーされていなかった複数のエッジケースを検証するテストが追加されました。これにより、テストスイートの堅牢性が向上します。追加されたテストは概ね的確ですが、一部に既存テストとの重複や、説明が誤解を招く可能性のある箇所が見受けられました。詳細については、具体的な改善提案をコメントとして記載しましたので、ご確認ください。

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/lib/__tests__/validators.test.ts`:
- Around line 101-103: Rename the test description so it reflects that it's
checking length-based validation rather than ReDoS resistance: update the `it`
title that wraps the
`expect(isValidGitHubUsername("a".repeat(1000))).toBe(false)` assertion to
something like "極端に長い文字列は無効 (長さ上限の確認)" or similar; keep the assertion and the
use of isValidGitHubUsername unchanged.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 961e43d1-ba22-4dd9-b0d5-185b3adff0b6

📥 Commits

Reviewing files that changed from the base of the PR and between 87d145d and b711fdc.

📒 Files selected for processing (1)

• src/lib/__tests__/validators.test.ts