# ADR-006: In-Memory Adapters for Testing

## Status
Accepted

## Context
The domain model needs to be tested without external dependencies (PostgreSQL, S3, etc.). We need fast, isolated tests that verify domain behavior.

## Decision
Implement in-memory adapters for all repository interfaces:
- InMemoryFieldSessionRepository
- InMemoryMissionRepository
- InMemoryDecisionCaseRepository
- InMemoryArtifactRegistry
- InMemoryEventStore
- InMemoryUnitOfWork

These adapters:
- Implement the same interfaces as production adapters
- Store data in memory (Map, Array)
- Can be reset between tests
- Are never used in production

## Consequences

### Positive
- Tests run in milliseconds
- No database setup required
- Parallel test execution safe
- Documents how repositories are used

### Negative
- Not production-realistic (no transactions, no persistence)
- Need separate integration tests for production adapters

## Related
- ADR-001: Domain knows nothing about AI
- ADR-002: Artifact is common base contract
- ADR-003: Event Sourcing for traceability