test(widgets): add unit tests for FileExplorer widget

[pranvxag]

Description

Adds a comprehensive unit test file for the FileExplorer widget
(packages/widgets/src/FileExplorer.ts), which had no test coverage.
14 tests cover navigation, selection, search, callbacks, and edge cases.

Related Issue

Closes #1730

Which package(s)?

@termuijs/widgets

Type of Change

• 🐛 Bug fix (type:bug)
• ✨ Feature (type:feature)
• 📝 Docs (type:docs)
• 🧪 Tests (type:testing)
• ♻️ Refactor (type:refactor)
• 🎨 Design / UX (type:design)
• ♿ Accessibility (type:accessibility)
• ⚡ Performance (type:performance)
• 🔧 DevOps / CI (type:devops)
• 🔒 Security (type:security)

Checklist

• ⭐ You starred the repo. The needs-star check blocks your merge otherwise.
• Tests pass locally: bun vitest run
• Build passes: bun run build
• Typecheck passes: bun run typecheck
• You read CONTRIBUTING.md.
• Your PR title follows type: short description.
• Widget state mutators call markDirty() (if your change affects rendering).
• No new any types without an inline comment explaining why.
• No unrelated refactors bundled into this PR.

GSSoC 2026 Participation

• You are a GSSoC 2026 contributor.
  https://gssoc.girlscript.org/profile/790b367a-48ea-45f6-af27-c353fb2d49cb

I reviewed each test case against the source code and verified all pass locally
with bun vitest run packages/widgets/.

Summary by CodeRabbit

• Tests
  • Added comprehensive test coverage for FileExplorer component, including file selection, navigation, filtering, and callback behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: c667acc1-c60d-4558-aaf9-9a2269b0e4ee

📥 Commits

Reviewing files that changed from the base of the PR and between 35c2213 and a4db6fb.

📒 Files selected for processing (1)

• packages/widgets/src/FileExplorer.test.ts

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📝 Walkthrough

Walkthrough

Adds packages/widgets/src/FileExplorer.test.ts, a new Vitest suite that covers all public behaviors of FileExplorer: constructor defaults, setFiles, next()/previous() navigation with bounds clamping, select() with callback and no-op, search() with case-insensitive filtering, and the current/selected getters.

Changes

FileExplorer Test Suite

Layer / File(s)	Summary
Test fixture and constructor tests packages/widgets/src/FileExplorer.test.ts	Adds the makeFiles helper returning a FileItem[] fixture; verifies root defaults to "./" and that a provided root option is stored correctly.
setFiles, next(), and previous() navigation packages/widgets/src/FileExplorer.test.ts	Verifies setFiles loads the file list and resets selectedIndex to 0; tests next() and previous() cursor movement including clamping at both ends.
select() and search() behavior packages/widgets/src/FileExplorer.test.ts	Tests select() accumulating paths, firing onSelect with the correct path, and being a no-op on an empty list; tests search() for case-insensitive filtering and empty-result returns.
current and selected getters packages/widgets/src/FileExplorer.test.ts	Asserts current is undefined with no files loaded and selected correctly aggregates all paths across multiple navigation and select() calls.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Suggested labels

gssoc:approved, quality:clean, type:testing, area:widgets, level:beginner

Suggested reviewers

• Karanjot786

Poem

🐇 A rabbit hopped through files one day,
Checking next() and previous() along the way.
select() fired—the callback rang true,
search() found matches (case-insensitive too)!
With every getter tested and green,
The cleanest explorer the warren has seen. 🌿

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: adding unit tests for the FileExplorer widget. It follows the repository's format and directly summarizes the changeset.
Description check	✅ Passed	The description includes all required sections from the template: Description, Related Issue, Which package(s), Type of Change, Checklist, and GSSoC participation. All sections are properly filled out.
Linked Issues check	✅ Passed	All requirements from issue #1730 are met: setFiles resetting index, next/previous navigation with clamping, select() adding paths and firing callbacks, select() handling empty lists, search() filtering case-insensitively, and getter methods returning correct values.
Out of Scope Changes check	✅ Passed	All changes are focused on adding test coverage for FileExplorer as specified in issue #1730. No unrelated modifications or refactors are present.
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 unit tests (beta)

• Create PR with unit tests

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[github-actions]

🎉 Thanks for your first PR to TermUI, @pranvxag.

Before your PR merges:

1. ⭐ Star the repo. Required. The star-check job blocks your merge otherwise.
2. ✅ All checks green: build, test, typecheck.
3. 🏷 PR title follows type: short description. Example: fix: handle empty list.
4. 🔗 Link your closing issue in the description.

GSSoC 2026 points come from labels after merge:

• gssoc:approved. +50 base points.
• level:beginner / intermediate / advanced / critical. +20 / +35 / +55 / +80.
• quality:clean / exceptional. x 1.2 / x 1.5.
• type:*. Stackable bonus.

Your reviewer responds within 48 hours. Ping @Karanjot786 on Discord for urgent help.

🚀 Welcome to the cohort.