[AIT-1141] fix(uts/objects): spec-side corrections from the LiveObjects deviations audit

[sacOO7]

• Fixes https://ably.atlassian.net/browse/AIT-1141

Summary

Spec-side corrections produced by a comprehensive audit that reconciled ably-js LiveObjects against the objects spec (objects-features.md + uts/objects), treating the reference implementation as the source of truth for behaviours that have already shipped. Every UTS unit test body was cross-checked against its derived implementation; the changes below fix spec tests that were unrunnable for a compliant SDK, assertions that contradicted the shipped public API, and pseudocode gaps that forced SDKs to document avoidable "deviations".

Companion implementation PR: ably/ably-js#2263 (source fixes + derived tests, kept in lock-step with the test IDs and bodies changed here).

Changes

1. Unsolicited-server-DETACHED tests were unrunnable — switched to client-side detach

RTO25b/access-throws-detached-0, RTO26b/write-throws-detached-0 and the RTO20e1 test injected an unsolicited server DETACHED and then asserted AWAIT_STATE channel.state == DETACHED. A compliant SDK immediately re-attaches on an unsolicited DETACHED (RTL13a), so the DETACHED state is transient, the AWAIT_STATE is a race, and — since every mock answers the re-ATTACH with ATTACHED — the precondition under test evaporates. This is the same reasoning that moved the proxy tier to an ERROR-based sequence in #501, and the spec's own RTPO19b test already used the correct pattern.

All three now reach DETACHED via a client-side AWAIT channel.detach() (solicited detach does not trigger RTL13a), and the shared helper mocks (setup_synced_channel, setup_synced_channel_no_ack) gain the DETACH → DETACHED responder the tests rely on.

2. RTO20e1 now covers both reachable states

The single DETACHED-injection test is replaced by a pair:

• objects/unit/RTO20e1/fails-on-channel-detached-0 — client-side detach while the operation waits for SYNCED.
• objects/unit/RTO20e1/fails-on-channel-failed-0 (new) — channel ERROR → FAILED, the same sequence as the proxy-tier test.

SUSPENDED is a connection-level state and is noted as out of scope for a channel-level unit mock.

3. RTO15 test asserts observable behaviour only

The test obtained result = AWAIT channel.object.publish([...]) and asserted result.serials — but RTO15 defines an internal function, and the realtime channel.object exposes no public publish. The test now drives the publish through a public mutation and asserts the outbound OBJECT ProtocolMessage shape; the PublishResult.serials contract is observed through its only consumer, the neighbouring RTO20 apply-on-ACK tests. The RTO15h clause itself is unchanged.

4. Public map semantics asserted as "lww"

The shipped public type is lowercase (ObjectsMapSemantics = 'lww' | 'unknown' in ably-js); asserting "LWW" could never match the public API. Five assertions in public_object_message.md updated. Reviewer note: please confirm ably-java's public rendering agrees — if it shipped uppercase, this becomes a cross-SDK reconciliation instead.

5. Pseudocode conventions and language-applicability notes

• uts/README.md gains a conventions section: == null means the language-appropriate absent value (undefined in JS); member access written as a call (instance.id()) is satisfied by a property where the features spec defines one (RTINS3); inputs that cannot be constructed in a language (non-string map keys in JS, null where it is indistinguishable from "omitted") make that test/row not applicable — sanctioned omissions rather than coverage gaps.
• The RTLC12e1 invalid-amounts table's null row and the RTLMV4b key-type test carry explicit applicability notes referencing those conventions.

This lets SDKs retire boilerplate "deviation" records for what are really language-mapping conventions.

6. Small fixes

• RTO24c1 subscribe call flipped to listener-first (subscribe(listener, { depth: 1 })), matching every other with-options call after the argument-order convergence.
• objects_faults.md unit-tier cross-reference updated to fails-on-channel-failed-0, the test whose ERROR-based sequence it describes.

Verification

The derived ably-js tests for every changed body pass spec-verbatim (full UTS unit suite: 1351 passing) — see ably/ably-js#2263 for the implementation side, including the two runtime bugs the same audit surfaced (sub-16-character object-id nonces, and one malformed inbound operation discarding its siblings).

Follow-ups (out of scope here)

• Nil operation payloads (COUNTER_INC without counterInc, MAP_SET without mapSet, MAP_REMOVE without mapRemove) are spec-silent; ably-js now warns-and-skips them consistently with RTLC7d3/RTLM15d4. Proposing explicit sub-clauses is left as a follow-up.
• uts-liveobjects predates main's OD2g/OD3g (json ObjectData) clauses — a merge from main is recommended before further UTS reconciliation.

[Copilot]

Pull request overview

This PR updates the Objects UTS specs and helpers to align unit/proxy-tier tests and pseudocode conventions with shipped LiveObjects behavior (treating the reference SDK behavior as authoritative), and to remove spec-side assertions/premises that are not reachable for compliant SDKs.

Changes:

• Updates unit-tier channel-fault tests to use client-side detaches and introduces an ERROR→FAILED variant for RTO20e1.
• Adjusts the RTO15 unit test to assert observable wire behavior via a public mutation, rather than asserting an internal publish API surface.
• Documents language-mapping/applicability conventions in UTS docs and adds explicit “not applicable” notes to specific value-type tables.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
uts/README.md	Adds pseudocode conventions for absent values, property access, and language-inapplicable inputs.
uts/objects/unit/value_types.md	Adds applicability note for non-string map key validation in JS/TS.
uts/objects/unit/realtime_object.md	Restructures several unit tests (RTO15, RTO20e1 variants, detach-related tests) and adjusts a subscribe call signature.
uts/objects/unit/public_object_message.md	Changes asserted public map semantics string from "LWW" to "lww".
uts/objects/unit/internal_live_counter_api.md	Adds applicability note for the null invalid-amount table row and annotates the row.
uts/objects/integration/proxy/objects_faults.md	Updates the unit-tier cross-reference text for the ERROR-based sequence.
uts/objects/helpers/standard_test_pool.md	Extends synced-channel helpers to respond to client DETACH with DETACHED.

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[ttypic]

Why it's in lowercase? Doesn't it simply represent enum in actual code?

[sacOO7]

You're right — semantics is the ObjectsMapSemantics enum, wire-encoded as an integer (OMP2: "values in order from zero: LWW"), and the lowercase form here was ably-js's idiomatic rendering (ObjectsMapSemantics = 'lww' string-literal union) leaking into the pseudo-code as if it were the canonical contract.

Reverted to the symbolic "LWW" in b394399, and added an Enum values bullet to the uts/README.md pseudocode conventions so each SDK's derivation is sanctioned explicitly: the enum member itself in typed SDKs (MapSemantics.LWW in ably-java), the string-literal union value in ably-js ('lww'). The ably-js derived test keeps asserting its real public API and now cites that convention instead of claiming lowercase is spec-mandated.