# Tree

**Test family:** `TRE`

Apply relevant search, filter, sort, action, and access item files in addition to the view-specific cases.

- **TRE-001** Root/leaf/branch, empty, one-level, deep, wide, lazy, and partially loaded trees announce structure.
- **TRE-002** Arrow/Home/End/typeahead/expand/collapse/select follow tree keyboard semantics.
- **TRE-003** Self-parent/cycle/orphan/duplicate node is prevented or safely represented.
- **TRE-004** Lazy-load error/retry does not mark branch empty; concurrent move/delete has truthful recovery.
- **TRE-005** Drag/reparent rejects illegal descendants and updates paths, permissions, rollups, and order atomically.
- **TRE-006** Filter/search shows ancestors/context and restores expansion predictably.

## Comprehensive per-item coverage

- **TRE-007** Render loading, empty, no-results, partial, ordinary, boundary-size, stale, offline, unauthorized, and error states distinctly.
- **TRE-008** Render values containing ASCII emoticons, emoji/ZWJ sequences, kaomoji, accents, mixed scripts, RTL, combining marks, invisible characters, and confusables.
- **TRE-009** Render null, empty, zero, false, unknown enum, deleted relation, long unbroken text, multiline text, media, links, and hostile markup canaries safely.
- **TRE-010** Verify visible rows/items/cards correspond exactly to the active query, filter, sort, group, page, tenant, and permission scope.
- **TRE-011** Change data while loading and while visible; avoid duplicates, omissions, jumping identity, stale totals, and interaction with the wrong item.
- **TRE-012** Select, focus, expand, edit, drag, open, and bulk-act using stable item identity even after reorder, virtualization, refresh, and pagination.
- **TRE-013** Deep-link, bookmark, share, refresh, duplicate tab, navigate back/forward, and restore; preserve only intended state and reject tampering.
- **TRE-014** Use owner, collaborator, restricted role, removed member, anonymous viewer, and another tenant; hidden data must not leak in counts, placeholders, caches, or timing.
- **TRE-015** Navigate and operate entirely by keyboard and screen reader; expose landmarks, headings, names, positions, selection, expansion, sort, errors, and live updates.
- **TRE-016** Test narrow/wide screens, portrait/landscape, 200% text, 400% reflow, high contrast, reduced motion, print, and touch targets.
- **TRE-017** Translate and lengthen text, switch RTL/LTR, locale sorting, number/date/currency formats, and time zone while view state exists.
- **TRE-018** Measure initial, incremental, sort/filter, scroll, selection, resize, and update latency at empty, ordinary, and supported maximum datasets.
- **TRE-019** Verify virtualization preserves focus, accessible position/count, selection, row height, sticky elements, and return position.
- **TRE-020** Retry after timeout, disconnect/reconnect, stale cache, replica lag, and partial response; show data age and never claim a false empty state.
- **TRE-021** Escape markup, URLs, filenames, formulas, and user content for the rendering context; links and actions must target the intended safe resource.
- **TRE-022** Change role, ownership, or record state between render and activation; reauthorize and refresh or reject the action clearly.
- **TRE-023** Export, print, copy, share, and screenshot the active view; preserve scope and formatting without exposing hidden fields or offscreen private data.
- **TRE-024** Verify analytics and audit distinguish viewed, loaded, exposed, selected, and acted-on items without collecting unnecessary content.
- **TRE-025** Save, rename, duplicate, reset, delete, and share view configuration; handle conflicts, invalid fields, schema changes, and revoked recipients.
- **TRE-026** Recover after renderer crash, corrupted saved state, invalid deep link, and unsupported browser capability with a usable default and diagnostic evidence.

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