RUDPClient/openspec/specs/gameplay-flow-regression-coverage/spec.md

gameplay-flow-regression-coverage Specification

Purpose

Define the required edit-mode regression coverage that protects the MVP gameplay flow from client gameplay input through authoritative server outputs and client-side application.

Requirements

Requirement: Gameplay-flow regressions cover client gameplay send and receive paths

The edit-mode regression suite SHALL cover the MVP client gameplay flow above the raw transport router, including ShootInput send routing and authoritative CombatEvent receive/apply behavior. Lane-policy assertions that belong to MessageManager MAY remain in MessageManagerTests, but gameplay-flow assertions MUST live in tests that exercise the client runtime or player-facing application path.

Scenario: Client fire intent regression proves dedicated ShootInput routing

• WHEN the controlled client gameplay path is exercised in an edit-mode regression test for a fire action
• THEN the test observes a ShootInput payload sent through the dedicated client shooting path
• THEN any lane-policy assertion in that flow remains limited to confirming the MVP reliable-lane contract rather than replacing broader gameplay-flow coverage

Scenario: Authoritative combat event regression proves client-side application

• WHEN an edit-mode regression test delivers an authoritative CombatEvent into the client gameplay receive path
• THEN the relevant player-owned authoritative state, presentation model, or diagnostics surface reflects the authoritative hit, damage, death, or rejection result
• THEN the test proves the outcome is applied from server truth rather than speculative local combat logic

Requirement: Gameplay-flow regressions cover remote authoritative snapshot decisions

The edit-mode regression suite SHALL cover the client path that buffers and consumes remote authoritative PlayerState snapshots, including stale rejection and interpolation/clamp behavior where practical.

Scenario: Remote interpolation regression proves buffering and stale rejection

• WHEN an edit-mode regression test feeds ordered and stale remote PlayerState snapshots into the client remote-player path
• THEN the test observes that newer authoritative snapshots enter the remote buffer while stale snapshots do not replace newer accepted state
• THEN the test verifies the resulting interpolation or latest-snapshot clamp decision matches the MVP remote-presentation rules

Requirement: Gameplay-flow regressions include a fake-transport authoritative round trip

The edit-mode regression suite SHALL include at least one deterministic fake-transport test that spans client send behavior, server-authoritative processing, and outgoing authoritative results. That round-trip regression MUST cover MoveInput -> PlayerState and ShootInput -> CombatEvent within the same MVP gameplay-flow suite, and it MUST assert that authoritative movement stepping follows the configured cadence contract.

Scenario: Fake-transport round trip preserves server authority across movement and combat

• WHEN an edit-mode regression test drives gameplay input through fake client/server transports and advances the server authority loop
• THEN the authoritative server path emits PlayerState snapshots in response to movement input using the configured authoritative movement cadence
• THEN the authoritative server path emits CombatEvent results in response to shooting input
• THEN the combined test protects both client single-session input flow and server multi-session authoritative behavior from regression

Requirement: Gameplay-flow regressions cover controlled-player correction decisions

The edit-mode regression suite SHALL cover the controlled-player reconciliation path after authoritative movement replay, including bounded correction for small cadence-aligned error, correction replacement under consecutive authoritative snapshots, and hard snap fallback for large or non-convergent divergence.

Scenario: Controlled-player reconciliation uses bounded correction for small error

• WHEN an edit-mode regression test applies an authoritative local PlayerState that leaves only small post-replay divergence
• THEN the controlled-player path keeps authoritative ownership of the snapshot
• THEN visible correction converges without an immediate hard snap on the acceptance frame

Scenario: Controlled-player reconciliation updates active correction on repeated small snapshots

• WHEN an edit-mode regression test feeds multiple authoritative local PlayerState updates whose residual divergence remains inside bounded-correction limits while a prior correction is still active
• THEN the controlled-player path replaces or folds the active correction according to the sync strategy
• THEN the test proves the client does not accumulate multiple stale correction tails

Scenario: Controlled-player reconciliation snaps on large divergence

• WHEN an edit-mode regression test applies an authoritative local PlayerState that leaves divergence beyond the configured snap threshold
• THEN the controlled-player path immediately applies the authoritative transform state
• THEN later prediction resumes from that authoritative baseline

Scenario: Controlled-player reconciliation snaps after failed convergence

• WHEN an edit-mode regression test feeds consecutive authoritative local PlayerState updates that keep bounded correction from converging within the configured budget
• THEN the controlled-player path escalates to a hard snap
• THEN the active correction state is cleared before later local prediction continues