**TerminalUI Coverage Fix:**
- Added explicit test for empty input case (lines 64-65 previously uncovered)
- Test "TerminalUI should explicitly handle empty input by re-prompting" validates
that multiple empty inputs are properly handled by re-prompting
- UI module coverage improved to near-100%
**MoveCommand Immutability (Anti-pattern Fix):**
- Changed MoveCommand fields from var to val: moveResult, previousBoard,
previousHistory, previousTurn
- Changed ResetCommand fields from var to val: previousBoard, previousHistory,
previousTurn
- Updated GameEngine to use .copy() instead of direct mutation when updating
command state (lines 88, 95, 103, 112)
- Removed 3 edge-case tests that relied on command mutation (now impossible with
immutable fields)
**MoveCommand Immutability Tests:**
- Added MoveCommandImmutabilityTest to verify:
- Fields cannot be mutated after creation
- equals/hashCode respect immutability invariant
- .copy() creates new instances with updated values
All tests pass; 100% core coverage maintained.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
Janis