parent item mutations

2026-07-08 11:39:42 +02:00
parent e20793a6b3
commit 9f1eca07e9
14 changed files with 784 additions and 103 deletions
@@ -0,0 +1,170 @@
+package cart
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	cart_messages "git.k6n.net/mats/go-cart-actor/proto/cart"
+)
+
+// Parent qty 1 → 2 resizes every direct child proportionally. Children all
+// start at qty 1 so the proportional factor of 2 doubles them.
+func TestChangeQuantity_ParentCascadesDoublingChildren(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 1, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 1, Price: 100, ParentId: &parentLine})
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 102, Sku: "C2", Quantity: 1, Price: 200, ParentId: &parentLine})
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: parentLine, Quantity: 2}); err != nil {
+		t.Fatalf("change qty: %v", err)
+	}
+
+	if g.Items[0].Quantity != 2 {
+		t.Errorf("parent qty = %d, want 2", g.Items[0].Quantity)
+	}
+	for _, it := range g.Items {
+		if it.Id == parentLine {
+			continue
+		}
+		if it.Quantity != 2 {
+			t.Errorf("child %s qty = %d, want 2 (cascaded from parent)", it.Sku, it.Quantity)
+		}
+	}
+}
+
+// Parent qty 2 → 3 with children at qty 2 → 3 (factor 3/2 = 1.5, integer math).
+func TestChangeQuantity_ParentCascadesNonIntegerRatio(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 2, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 2, Price: 100, ParentId: &parentLine})
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: parentLine, Quantity: 3}); err != nil {
+		t.Fatalf("change qty: %v", err)
+	}
+
+	// parent: 2 -> 3 (direct set), child: 2 * 3 / 2 = 3
+	if g.Items[0].Quantity != 3 {
+		t.Errorf("parent qty = %d, want 3", g.Items[0].Quantity)
+	}
+	if g.Items[1].Quantity != 3 {
+		t.Errorf("child qty = %d, want 3 (proportional scale)", g.Items[1].Quantity)
+	}
+}
+
+// Scale-down that would round to 0 (parent 2 → 1, child qty 1 → (1*1)/2 = 0)
+// must clamp to 1 so the child is never silently dropped by integer math.
+func TestChangeQuantity_ParentScaleDownFloorsAtOne(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 2, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 1, Price: 100, ParentId: &parentLine})
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: parentLine, Quantity: 1}); err != nil {
+		t.Fatalf("change qty: %v", err)
+	}
+
+	if g.Items[0].Quantity != 1 {
+		t.Errorf("parent qty = %d, want 1", g.Items[0].Quantity)
+	}
+	if g.Items[1].Quantity != 1 {
+		t.Errorf("child qty = %d, want 1 (floor; integer math dropped to 0 without clamp)", g.Items[1].Quantity)
+	}
+}
+
+// Setting parent qty to 0 delegates to RemoveItem so the existing parent→
+// child cascade takes over. Unrelated lines are left untouched.
+func TestChangeQuantity_ZeroCascadesRemoval(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 1, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 1, Price: 100, ParentId: &parentLine})
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 200, Sku: "OTHER", Quantity: 1, Price: 500})
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: parentLine, Quantity: 0}); err != nil {
+		t.Fatalf("change qty 0: %v", err)
+	}
+
+	if len(g.Items) != 1 {
+		t.Fatalf("items = %d, want 1 (only OTHER survives)", len(g.Items))
+	}
+	if g.Items[0].Sku != "OTHER" {
+		t.Errorf("remaining sku = %q, want OTHER", g.Items[0].Sku)
+	}
+}
+
+// Changing a child's qty directly updates only that child — siblings and
+// the parent are untouched. (The UI no longer exposes this control, but
+// the HTTP surface still allows it for tools & direct API calls.)
+func TestChangeQuantity_ChildDoesNotCascade(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 1, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 1, Price: 100, ParentId: &parentLine})
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 102, Sku: "C2", Quantity: 1, Price: 200, ParentId: &parentLine})
+	targetChild := g.Items[1].Id
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: targetChild, Quantity: 3}); err != nil {
+		t.Fatalf("change child qty: %v", err)
+	}
+
+	for _, it := range g.Items {
+		switch it.Id {
+		case parentLine:
+			if it.Quantity != 1 {
+				t.Errorf("parent qty = %d, want 1 (untouched on child edit)", it.Quantity)
+			}
+		case targetChild:
+			if it.Quantity != 3 {
+				t.Errorf("target child qty = %d, want 3", it.Quantity)
+			}
+		default:
+			// Sibling
+			if it.Quantity != 1 {
+				t.Errorf("sibling %s qty = %d, want 1 (untouched on child edit)", it.Sku, it.Quantity)
+			}
+		}
+	}
+}
+
+// Cascade descends into grandchildren so deeply nested accessory trees
+// remain internally consistent with the top-level parent change.
+func TestChangeQuantity_NestedChildren(t *testing.T) {
+	reg := NewCartMultationRegistry(NewCartMutationContext(nil))
+	g := NewCartGrain(1, time.Now())
+	ctx := context.Background()
+
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 100, Sku: "P", Quantity: 1, Price: 1000})
+	parentLine := g.Items[0].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 101, Sku: "C1", Quantity: 1, Price: 100, ParentId: &parentLine})
+	childLine := g.Items[1].Id
+	mustApply(t, reg, g, &cart_messages.AddItem{ItemId: 102, Sku: "G1", Quantity: 1, Price: 50, ParentId: &childLine})
+
+	if _, err := reg.Apply(ctx, g, &cart_messages.ChangeQuantity{Id: parentLine, Quantity: 2}); err != nil {
+		t.Fatalf("change qty: %v", err)
+	}
+
+	// parent 1 -> 2; child 1 -> 2 (parent -> child cascade); grandchild 1 -> 2 (child -> grandchild cascade)
+	for _, it := range g.Items {
+		if it.Quantity != 2 {
+			t.Errorf("line %s qty = %d, want 2 (nested cascade)", it.Sku, it.Quantity)
+		}
+	}
+}