first

backend/test/pricing/service_test.go

@@ -0,0 +1,142 @@
+package pricing_test
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/google/uuid"
+
+	"backend/internal/modules/pricing"
+)
+
+// fakeRepository is an in-memory pricing.Repository used to unit-test
+// pricing.Service without a real database.
+type fakeRepository struct {
+	tiers map[uuid.UUID]*pricing.PriceTier
+}
+
+func newFakeRepository() *fakeRepository {
+	return &fakeRepository{tiers: map[uuid.UUID]*pricing.PriceTier{}}
+}
+
+func (r *fakeRepository) Create(_ context.Context, t *pricing.PriceTier) error {
+	cp := *t
+	r.tiers[t.ID] = &cp
+	return nil
+}
+
+func (r *fakeRepository) FindByID(_ context.Context, id uuid.UUID) (*pricing.PriceTier, error) {
+	t, ok := r.tiers[id]
+	if !ok {
+		return nil, pricing.ErrNotFound
+	}
+	cp := *t
+	return &cp, nil
+}
+
+func (r *fakeRepository) ListByProduct(_ context.Context, productID uuid.UUID) ([]*pricing.PriceTier, error) {
+	var list []*pricing.PriceTier
+	for _, t := range r.tiers {
+		if t.ProductID == productID {
+			cp := *t
+			list = append(list, &cp)
+		}
+	}
+	return list, nil
+}
+
+func (r *fakeRepository) Update(_ context.Context, t *pricing.PriceTier) error {
+	if _, ok := r.tiers[t.ID]; !ok {
+		return pricing.ErrNotFound
+	}
+	cp := *t
+	r.tiers[t.ID] = &cp
+	return nil
+}
+
+func (r *fakeRepository) Delete(_ context.Context, id uuid.UUID) error {
+	if _, ok := r.tiers[id]; !ok {
+		return pricing.ErrNotFound
+	}
+	delete(r.tiers, id)
+	return nil
+}
+
+func TestService_PriceForQuantity_MultipliesTierPrice(t *testing.T) {
+	repo := newFakeRepository()
+	svc := pricing.NewService(repo)
+	ctx := context.Background()
+
+	productID := uuid.New()
+	unitID := uuid.New()
+
+	// "5 kg -> 45.00" tier, spec section 16 example.
+	tier, err := svc.Create(ctx, productID, unitID, 5, 4500, 0)
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	total, gotTier, err := svc.PriceForQuantity(ctx, tier.ID, 2)
+	if err != nil {
+		t.Fatalf("PriceForQuantity() error = %v", err)
+	}
+	if total != 9000 {
+		t.Fatalf("PriceForQuantity() total = %d, want 9000 (2x 4500)", total)
+	}
+	if gotTier.ID != tier.ID {
+		t.Fatalf("PriceForQuantity() returned tier %s, want %s", gotTier.ID, tier.ID)
+	}
+}
+
+func TestService_PriceForQuantity_ZeroOrNegativeMultiplierTreatedAsOne(t *testing.T) {
+	repo := newFakeRepository()
+	svc := pricing.NewService(repo)
+	ctx := context.Background()
+
+	tier, err := svc.Create(ctx, uuid.New(), uuid.New(), 1, 1000, 0)
+	if err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	total, _, err := svc.PriceForQuantity(ctx, tier.ID, 0)
+	if err != nil {
+		t.Fatalf("PriceForQuantity() error = %v", err)
+	}
+	if total != 1000 {
+		t.Fatalf("PriceForQuantity() with multiplier=0 total = %d, want 1000 (treated as 1x)", total)
+	}
+}
+
+func TestService_PriceForQuantity_UnknownTierRejected(t *testing.T) {
+	svc := pricing.NewService(newFakeRepository())
+	_, _, err := svc.PriceForQuantity(context.Background(), uuid.New(), 1)
+	if !errors.Is(err, pricing.ErrNotFound) {
+		t.Fatalf("PriceForQuantity() error = %v, want ErrNotFound", err)
+	}
+}
+
+func TestService_ListByProduct_FiltersByProduct(t *testing.T) {
+	repo := newFakeRepository()
+	svc := pricing.NewService(repo)
+	ctx := context.Background()
+
+	productA := uuid.New()
+	productB := uuid.New()
+	unitID := uuid.New()
+
+	if _, err := svc.Create(ctx, productA, unitID, 1, 1000, 0); err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+	if _, err := svc.Create(ctx, productB, unitID, 1, 2000, 0); err != nil {
+		t.Fatalf("Create() error = %v", err)
+	}
+
+	list, err := svc.ListByProduct(ctx, productA)
+	if err != nil {
+		t.Fatalf("ListByProduct() error = %v", err)
+	}
+	if len(list) != 1 || list[0].ProductID != productA {
+		t.Fatalf("ListByProduct(productA) = %+v, want exactly one tier for productA", list)
+	}
+}