Add more tests

src/engine/__tests__/EntityManager.test.ts

@@ -90,4 +90,43 @@ describe('EntityManager', () => {
     expect(entityManager.getActorsAt(1, 1).map(a => a.id)).toEqual([2]);
   });
 
+
+  it('should handle removing non-existent actor gracefully', () => {
+    // Should not throw
+    entityManager.removeActor(999);
+  });
+
+  it('should handle moving non-existent actor gracefully', () => {
+    // Should not throw
+    entityManager.moveActor(999, { x: 0, y: 0 }, { x: 1, y: 1 });
+  });
+
+  it('should handle moving an actor that is not in the grid at expected position (inconsistent state)', () => {
+    const actor: Actor = { id: 1, pos: { x: 0, y: 0 } } as any;
+    // Add to actors map but NOT to grid (simulating desync)
+    mockWorld.actors.set(1, actor);
+    
+    // Attempt move
+    entityManager.moveActor(1, { x: 0, y: 0 }, { x: 1, y: 1 });
+    
+    expect(actor.pos.x).toBe(1);
+    expect(actor.pos.y).toBe(1);
+    // Should be added to new position in grid
+    expect(entityManager.getActorsAt(1, 1).map(a => a.id)).toContain(1);
+  });
+  
+  it('should handle moving an actor that is in grid but ID not found in list (very rare edge case)', () => {
+     // Manually pollute grid with empty array for old pos
+     // This forces `ids` to exist but `indexOf` to return -1
+     const idx = 0; // 0,0
+     // @ts-ignore
+     entityManager.grid.set(idx, [999]); // occupied by someone else
+     
+     const actor: Actor = { id: 1, pos: { x: 0, y:0 } } as any;
+     mockWorld.actors.set(1, actor);
+     
+     entityManager.moveActor(1, { x: 0, y: 0 }, { x: 1, y: 1 });
+     expect(actor.pos).toEqual({ x: 1, y: 1 });
+  });
+
 });