1 files changed, 201 insertions, 0 deletions
diff --git a/internal/game/correct_quality_merge_test.go b/internal/game/correct_quality_merge_test.go
new file mode 100644
index 0000000..d54c8c9
--- /dev/null
+++ b/internal/game/correct_quality_merge_test.go
@@ -0,0 +1,201 @@
+package game
+
+// Regression: every stack-creation and stack-merge site must agree on the
+// Quality/MaxQuality a fresh stack gets (newInventorySlot / stackProps).
+// Pickups merge only into a stack with those exact properties, so a stack
+// produced by crafting, harvesting, or ammo removal with Quality 0 could no
+// longer be merged into - a full inventory then refused a pickup of an item
+// the player already carried.
+
+import (
+	"path/filepath"
+	"testing"
+
+	"thehouseoficarus/internal/item"
+	"thehouseoficarus/internal/net"
+	"thehouseoficarus/internal/player"
+)
+
+const correctQualityItemYAML = `id: correct_quality_gem
+name: correct quality gem
+stackable: true
+max_quality: 5
+craft:
+  - type: crafting
+    ingredients:
+      - items:
+          - correct_quality_shard
+        quantity: 1
+    xp: 1
+    ticks_per_cycle: 1
+`
+
+func seedCorrectQualityItems(t *testing.T, h *harness) {
+	t.Helper()
+	writeSeedFile(t, filepath.Join(h.dir, "items", "correct_quality_gem.yaml"), []byte(correctQualityItemYAML))
+	writeSeedFile(t, filepath.Join(h.dir, "items", "correct_quality_shard.yaml"),
+		[]byte("id: correct_quality_shard\nname: correct quality shard\nstackable: true\nmax_quality: 5\nvalue: 1\n"))
+}
+
+// fillInventoryExcept occupies every slot but slot 0 with filler.
+func fillInventoryExcept(p *player.Player) {
+	for i := 0; i < 28; i++ {
+		if i != 0 {
+			p.SetInvSlot(i, &player.InventorySlot{ItemID: "filler", Quantity: 1})
+		}
+	}
+}
+
+// TestStackPropsMatchNewInventorySlot guards the one rule that stack creation
+// and stack merging both depend on: the helper the craft/harvest/ammo sites
+// use must stamp what newInventorySlot stamps.
+func TestStackPropsMatchNewInventorySlot(t *testing.T) {
+	h := newHarness(t)
+	seedCorrectQualityItems(t, h)
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		gem := h.g.newInventorySlot("correct_quality_gem", 1)
+		if q, mq := stackProps(mustLoadItem(t, h.g, "correct_quality_gem")); q != gem.Quality || mq != gem.MaxQuality {
+			t.Errorf("stackProps = (%d,%d), newInventorySlot = (%d,%d)", q, mq, gem.Quality, gem.MaxQuality)
+		}
+		shard := h.g.newInventorySlot("correct_quality_shard", 1)
+		if q, mq := stackProps(mustLoadItem(t, h.g, "correct_quality_shard")); q != shard.Quality || mq != shard.MaxQuality {
+			t.Errorf("quality-free stackProps = (%d,%d), newInventorySlot = (%d,%d)", q, mq, shard.Quality, shard.MaxQuality)
+		}
+	})
+}
+
+func TestCraftOutputMergesIntoQualityStack(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice")
+	p := h.seedCharacter("alice", "alice")
+	seedCorrectQualityItems(t, h)
+
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		def := mustLoadItem(t, h.g, "correct_quality_gem")
+		p.SetInvSlot(0, &player.InventorySlot{ItemID: def.ID, Quantity: 10, Quality: 5, MaxQuality: 5})
+		fillInventoryExcept(p)
+
+		if !craftOutputFits(p, def.ID, def) {
+			t.Fatal("a full inventory must accept a craft output that merges into an identical stack")
+		}
+		if !placeCraftOutput(p, def.ID, def, 2) {
+			t.Fatal("craft output was not placed")
+		}
+		if slot := p.InvSlot(0); slot.Quantity != 12 || slot.Quality != 5 || slot.MaxQuality != 5 {
+			t.Errorf("merged stack = %+v, want quantity 12 at quality 5", slot)
+		}
+
+		// A differently qualified stack is not a merge target: the same
+		// full inventory must report that nothing fits.
+		p.SetInvSlot(0, &player.InventorySlot{ItemID: def.ID, Quantity: 10, Quality: 1, MaxQuality: 5})
+		if craftOutputFits(p, def.ID, def) {
+			t.Error("craft output would merge into a stack with a different quality")
+		}
+		if placeCraftOutput(p, def.ID, def, 2) {
+			t.Error("craft output was placed with no free slot and no matching stack")
+		}
+	})
+}
+
+func TestCraftOutputCreatesStackWithFreshProps(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice")
+	p := h.seedCharacter("alice", "alice")
+	seedCorrectQualityItems(t, h)
+
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		def := mustLoadItem(t, h.g, "correct_quality_gem")
+		if !placeCraftOutput(p, def.ID, def, 3) {
+			t.Fatal("craft output was not placed in an empty inventory")
+		}
+		slot := p.InvSlot(0)
+		if slot == nil || slot.ItemID != def.ID {
+			t.Fatalf("slot 0 = %+v", slot)
+		}
+		if q, mq := h.g.pickedStackProps(def.ID); slot.Quality != q || slot.MaxQuality != mq {
+			t.Fatalf("crafted stack %+v does not match what a pickup receives (%d,%d)", slot, q, mq)
+		}
+	})
+}
+
+func TestPickupMergesIntoHarvestedStackWhenFull(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice")
+	p := h.seedCharacter("alice", "alice")
+	writeSeedFile(t, filepath.Join(h.dir, "items", hardeningCropID+".yaml"),
+		[]byte("id: test_potato\nname: test potato\nstackable: true\nmax_quality: 5\n"))
+
+	conn := newChanConn()
+	sess := &net.Session{Conn: conn, Player: p}
+	sess.SetState(net.StateGame)
+
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		readyHarvest(p, 3, 3)
+		h.g.advanceHarvest(sess, p)
+
+		stack := p.InvSlot(0)
+		if stack == nil || stack.ItemID != hardeningCropID {
+			t.Fatalf("harvested stack = %+v", stack)
+		}
+		quality, maxQuality := h.g.pickedStackProps(hardeningCropID)
+		if stack.Quality != quality || stack.MaxQuality != maxQuality {
+			t.Fatalf("harvested stack %+v does not match what a pickup receives (%d,%d)", stack, quality, maxQuality)
+		}
+
+		// A full inventory must still merge a ground pickup into the stack
+		// the harvest just created.
+		fillInventoryExcept(p)
+		h.g.World.AddGroundItem(p.RoomID, hardeningCropID, 2)
+		h.g.doGet(sess, "test potato")
+
+		if got := p.CountItem(hardeningCropID); got != 5 {
+			t.Errorf("potatoes carried = %d, want 5", got)
+		}
+		if got := h.g.World.GroundItems(p.RoomID)[hardeningCropID]; got != 0 {
+			t.Errorf("ground potatoes = %d, want 0 (they fit the existing stack)", got)
+		}
+	})
+}
+
+func TestPickupMergesIntoAmmoReturnedStack(t *testing.T) {
+	h := newHarness(t)
+	h.seedAccount("alice")
+	p := h.seedCharacter("alice", "alice")
+	seedCorrectQualityItems(t, h)
+
+	conn := newChanConn()
+	sess := &net.Session{Conn: conn, Player: p}
+	sess.SetState(net.StateGame)
+
+	h.g.RunOnOwner(func() {
+		h.g.ItemStore.Reload(h.dir)
+		p.Equipment[item.SlotAmmo] = "correct_quality_shard"
+		p.AmmoQty = 4
+		if !h.g.unequipAmmo(p) {
+			t.Fatal("unequipAmmo refused an empty inventory")
+		}
+		stack := p.InvSlot(0)
+		if stack == nil || stack.ItemID != "correct_quality_shard" {
+			t.Fatalf("returned ammo stack = %+v", stack)
+		}
+		quality, maxQuality := h.g.pickedStackProps("correct_quality_shard")
+		if stack.Quality != quality || stack.MaxQuality != maxQuality {
+			t.Fatalf("returned ammo stack %+v does not match what a pickup receives (%d,%d)", stack, quality, maxQuality)
+		}
+
+		fillInventoryExcept(p)
+		h.g.World.AddGroundItem(p.RoomID, "correct_quality_shard", 3)
+		h.g.doGet(sess, "correct quality shard")
+
+		if got := p.CountItem("correct_quality_shard"); got != 7 {
+			t.Errorf("shards carried = %d, want 7", got)
+		}
+		if got := h.g.World.GroundItems(p.RoomID)["correct_quality_shard"]; got != 0 {
+			t.Errorf("ground shards = %d, want 0 (they fit the returned stack)", got)
+		}
+	})
+}