fix tests

src/test/BuildingTest.cpp

@@ -348,6 +348,7 @@ TEST_CASE("BuildingSystem: smelter input buffer fills from adjacent west-flowing
     // Place west-flowing belt at (2,0): belt flows West, delivers to smelter.
     belts.placeBelt(QPoint(2, 0), Rotation::West);
     belts.tryPutItem(QPoint(2, 0), makeItem("iron_ore"));
+    belts.tick();
 
     bs.tickBeltPull();
 
@@ -500,6 +501,7 @@ TEST_CASE("BuildingSystem: reprocessing plant produces one cycle output then sta
     for (int i = 0; i < 5; ++i)
     {
         belts.tryPutItem(QPoint(-1, 0), makeItem("scrap"));
+        belts.tick();
         bs.tickBeltPull();
     }