1 files changed, 55 insertions, 0 deletions
diff --git a/internal/game/inventory_pickup_test.go b/internal/game/inventory_pickup_test.go
new file mode 100644
index 0000000..a0d267e
--- /dev/null
+++ b/internal/game/inventory_pickup_test.go
@@ -0,0 +1,55 @@
+package game
+
+// Regression: picking up a stackable item must merge into an existing stack
+// even when every inventory slot is occupied — capacity is required only
+// when a NEW slot is needed, matching the get-all paths.
+
+import (
+	"path/filepath"
+	"testing"
+
+	"thehouseoficarus/internal/net"
+	"thehouseoficarus/internal/player"
+)
+
+func TestPickupMergesIntoFullInventory(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice", "pw", false)
+	p := h.seedCharacter("alice", "alice")
+	writeSeedFile(t, filepath.Join(h.dir, "items", "chips.yaml"), []byte("id: chips\nname: chips\nstackable: true\n"))
+	sess := &net.Session{Conn: newChanConn(), Player: p, State: net.StateGame}
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		for i := 0; i < 28; i++ {
+			p.SetInvSlot(i, &player.InventorySlot{ItemID: "filler", Quantity: 1})
+		}
+		p.SetInvSlot(0, &player.InventorySlot{ItemID: "chips", Quantity: 10})
+		h.g.World.AddGroundItem(1, "chips", 5)
+		h.g.doGet(sess, "chips")
+		if got := countChips(p); got != 15 {
+			t.Errorf("pickup rejected despite existing chip stack: have %d, want 15", got)
+		}
+	})
+}
+
+func TestPickupFullInventoryWithoutStackStillRefused(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice", "pw", false)
+	p := h.seedCharacter("alice", "alice")
+	writeSeedFile(t, filepath.Join(h.dir, "items", "chips.yaml"), []byte("id: chips\nname: chips\nstackable: true\n"))
+	sess := &net.Session{Conn: newChanConn(), Player: p, State: net.StateGame}
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		for i := 0; i < 28; i++ {
+			p.SetInvSlot(i, &player.InventorySlot{ItemID: "filler", Quantity: 1})
+		}
+		h.g.World.AddGroundItem(1, "chips", 5)
+		h.g.doGet(sess, "chips")
+		if got := countChips(p); got != 0 {
+			t.Errorf("pickup without an existing stack must be refused, have %d", got)
+		}
+		if got := h.g.World.GroundItems(1)["chips"]; got != 5 {
+			t.Errorf("refused pickup must leave the ground stack intact, have %d", got)
+		}
+	})
+}