# In-app message, chat, feed item

**Test family:** `CHT`

- **CHT-001** Send empty, ordinary, multiline, Unicode, long, formatted, link, mention, attachment, and safe markup-canary content.
- **CHT-002** Optimistic send transitions pending→sent/failed once; retry does not duplicate.
- **CHT-003** Messages order consistently under clock skew, reconnect, pagination, and concurrent senders.
- **CHT-004** Edit/delete/reaction/reply/thread actions update all clients and preserve audit as promised.
- **CHT-005** Read/unread, delivery, presence, and typing indicators are eventual hints, not false guarantees.
- **CHT-006** Blocked/removed/unauthorized users cannot send, fetch history, resolve attachments, or receive push previews.
- **CHT-007** Offline queue, reconnect, duplicate events, and out-of-order websocket messages converge.
- **CHT-008** Notification preview respects lock-screen and sensitive-content policy.

## Comprehensive per-item coverage

- **CHT-009** Create absent, empty, ordinary, boundary-size, and over-limit content; distinguish missing data, empty content, and intentionally blank content.
- **CHT-010** Use ASCII emoticons such as `:)`, `:-)`, `;)`, `:D`, `:(`, and `<3`; preserve them exactly or reject them with a specific product rule.
- **CHT-011** Use kaomoji and complex emoji including skin tones, flags, keycaps, variation selectors, and ZWJ sequences; preserve complete graphemes.
- **CHT-012** Use accents, decomposed forms, CJK, Arabic, Hebrew, mixed direction, confusables, and invisible characters; keep rendering and identity unambiguous.
- **CHT-013** Use long words, many short lines, one long line, tabs, mixed line endings, trailing spaces, and control characters through every supported transport.
- **CHT-014** Use inert HTML/script, Markdown, template, SQL, command, path, CSV-formula, header, and log-forging canaries; never execute content as control.
- **CHT-015** Compare typing, paste, rich paste, upload, import, API, mobile, automation, and migration paths; apply the same content contract.
- **CHT-016** Save, preview, reopen, edit, copy, quote, reply, forward, notify, search, index, export, and delete; preserve intended content and access.
- **CHT-017** Verify content encoding, charset declaration, BOM, compression, chunking, multipart boundaries, and transcoding do not corrupt data.
- **CHT-018** Attempt access as owner, collaborator, removed member, external guest, anonymous viewer, and another tenant; reauthorize every delivery path.
- **CHT-019** Change access after a link, preview, notification, or cached representation exists; revoke stale copies where the contract promises it.
- **CHT-020** Edit concurrently, retry after timeout, and resubmit the same content; avoid silent overwrite, duplicates, and reordered versions.
- **CHT-021** Force storage, scanner, renderer, indexer, notification, export, and downstream integration failures; expose partial state and recovery.
- **CHT-022** Test keyboard, screen reader, zoom, reflow, high contrast, reduced motion, captions/alternatives, and focus for creating and consuming content.
- **CHT-023** Translate UI and content, switch locale and direction, and render unsupported glyphs; preserve data even when fonts or layout degrade.
- **CHT-024** Measure create, upload, render, search, download, and delete latency at normal and supported boundary sizes.
- **CHT-025** Inspect URLs, metadata, filenames, previews, logs, telemetry, caches, backups, notifications, and exports for sensitive-content leakage.
- **CHT-026** Apply malware, abuse, spam, moderation, and policy handling without exposing scanner details or destroying innocent content silently.
- **CHT-027** Delete, restore, expire, retain, place on hold, export, and purge content; make user-visible state match storage and legal policy.
- **CHT-028** Verify hashes, sizes, versions, ownership, timestamps, and audit events across replicas and transformations so corruption is detectable.

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