= test-kernel

== purpose

Tests for the core kernel orchestration logic: retry coordination and inference replay. Verifies that the `DefaultRetryCoordinator` correctly manages retry attempts and that inference events replay to the correct provider state.

== responsibilities

* Test `DefaultRetryCoordinator` retry policy enforcement (max attempts, backoff, exhaustion)
* Test `ReplayInferenceProvider` to ensure inference events replay correctly through the inference projector

== non-responsibilities

* Does not test the full session orchestrator lifecycle
* Does not test infrastructure retry mechanisms (e.g., HTTP retry)
* Does not test UI or application layers

== key types

=== MockOrchestrationEventReplayer
* **kind**: class
* **purpose**: Test double implementing `EventReplayer<OrchestrationState>`. Returns pre-configured states by session ID; defaults to `RUNNING` with `stage-1`.

=== MockSessionEventReplayer
* **kind**: class
* **purpose**: Test double implementing `EventReplayer<SessionState>`. Returns pre-configured states by session ID; defaults to `ACTIVE`.

=== DefaultRetryCoordinatorTest
* **kind**: JUnit 5 test class
* **purpose**: Tests retry coordination logic — max retries, exponential backoff duration, retry exhaustion behavior.

=== ReplayInferenceProviderTest
* **kind**: JUnit 5 test class
* **purpose**: Tests that inference events streamed through the replay mechanism produce correct `InferenceState`.

== event flow

*inbound:* Programmatically constructed events and state objects injected into mock replayers.

*outbound:* Assertions on retry coordinator state (attempt count, delay values) and replayed inference state.

== integration points

* `:core:kernel` — `DefaultRetryCoordinator`, orchestration state and event types
* `:core:inference` — `InferenceProjector`, `InferenceState`, `InferenceRepository`
* `:core:sessions` — `SessionState`, `SessionStatus`
* `:core:events` — event payload types, `EventReplayer` interface
* `:testing:fixtures` — mock replayers and state builders

== invariants

* Retry coordinator respects max attempt limits — exceeding them marks the operation as exhausted
* Event replay produces the same inference state regardless of the number of replay passes

== PlantUML diagram

[plantuml, test-kernel, "png"]
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include::../../diagrams/test-kernel.puml[]
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== known issues

* Mock replayers provide pre-canned states rather than true event-sourced replay — tests do not verify the replay machinery itself, only the components that consume replay output

== open questions

* Should the tests also cover the `DefaultRetryCoordinator` integration with the event store?
* Should there be a full `EventStore` + `RetryCoordinator` integration test here?