Enhance procurement lot estimated value aggregation and add unit tests

- Updated the `AggregateProcurementLotEstimatedValue` function to reject mixed currencies and allow empty lot currencies, ensuring accurate aggregation of estimated values.
- Introduced new unit tests in `entity_test.go` to validate the behavior of the aggregation function under various scenarios, including mixed currencies and empty lot currencies.
- Refactored budget calculation in `budget_test.go` to utilize the new aggregation logic, improving consistency in budget retrieval.

This update improves the handling of estimated values in procurement lots, enhancing the reliability of the tender management system.

internal/tender/entity.go

@@ -309,18 +309,37 @@ func (t *Tender) HasEstimatedValue() bool {
 	return value > 0
 }
 
-// AggregateProcurementLotEstimatedValue sums lot-level estimated values and returns the first lot currency found.
+// AggregateProcurementLotEstimatedValue sums lot-level estimated values when all non-empty
+// lot currencies match. Conflicting currencies are not aggregated.
 func AggregateProcurementLotEstimatedValue(lots []ProcurementLot) (value float64, currency string) {
+	var refCurrency string
+	for _, lot := range lots {
+		if lot.EstimatedValue <= 0 {
+			continue
+		}
+		c := strings.TrimSpace(lot.Currency)
+		if c == "" {
+			continue
+		}
+		if refCurrency == "" {
+			refCurrency = c
+			continue
+		}
+		if c != refCurrency {
+			return 0, ""
+		}
+	}
+
 	for _, lot := range lots {
 		if lot.EstimatedValue <= 0 {
 			continue
 		}
 		value += lot.EstimatedValue
-		if currency == "" {
-			currency = strings.TrimSpace(lot.Currency)
 	}
+	if value <= 0 {
+		return 0, ""
 	}
-	return value, currency
+	return value, refCurrency
 }
 
 // ResolvedEstimatedValueAndCurrency returns the tender-level estimated value when set,

internal/tender/entity_test.go

@@ -15,6 +15,29 @@ func TestAggregateProcurementLotEstimatedValue(t *testing.T) {
 	}
 }
 
+func TestAggregateProcurementLotEstimatedValueRejectsMixedCurrencies(t *testing.T) {
+	value, currency := AggregateProcurementLotEstimatedValue([]ProcurementLot{
+		{EstimatedValue: 100000, Currency: "EUR"},
+		{EstimatedValue: 250000, Currency: "USD"},
+	})
+	if value != 0 || currency != "" {
+		t.Fatalf("expected no aggregation for mixed currencies, got value=%v currency=%q", value, currency)
+	}
+}
+
+func TestAggregateProcurementLotEstimatedValueAllowsEmptyLotCurrency(t *testing.T) {
+	value, currency := AggregateProcurementLotEstimatedValue([]ProcurementLot{
+		{EstimatedValue: 100000, Currency: "EUR"},
+		{EstimatedValue: 250000},
+	})
+	if value != 350000 {
+		t.Fatalf("expected total 350000, got %v", value)
+	}
+	if currency != "EUR" {
+		t.Fatalf("expected currency EUR, got %q", currency)
+	}
+}
+
 func TestResolvedEstimatedValueAndCurrencyUsesLotsWhenTopLevelMissing(t *testing.T) {
 	tender := &Tender{
 		Currency: "EUR",

ted/aggregate.go

@@ -0,0 +1,41 @@
+package ted
+
+import "strings"
+
+type valuedAmount struct {
+	value    float64
+	currency string
+}
+
+// aggregateSameCurrencyAmounts sums values only when every non-empty currency matches.
+// Lots with an empty currency are included; conflicting currencies yield zero.
+func aggregateSameCurrencyAmounts(amounts []valuedAmount) (total float64, currency string) {
+	var refCurrency string
+	for _, item := range amounts {
+		if item.value <= 0 {
+			continue
+		}
+		c := strings.TrimSpace(item.currency)
+		if c == "" {
+			continue
+		}
+		if refCurrency == "" {
+			refCurrency = c
+			continue
+		}
+		if c != refCurrency {
+			return 0, ""
+		}
+	}
+
+	for _, item := range amounts {
+		if item.value <= 0 {
+			continue
+		}
+		total += item.value
+	}
+	if total <= 0 {
+		return 0, ""
+	}
+	return total, refCurrency
+}

ted/budget_test.go

@@ -56,3 +56,29 @@ func TestContractNoticeGetBudgetSumsAllLots(t *testing.T) {
 		t.Fatalf("expected EUR, got %q", currency)
 	}
 }
+
+func TestContractNoticeGetBudgetRejectsMixedCurrencies(t *testing.T) {
+	cn := ContractNotice{
+		ProcurementProjectLots: []ProcurementProjectLot{
+			{
+				ProcurementProject: &ProcurementProject{
+					RequestedTenderTotal: &RequestedTenderTotal{
+						EstimatedOverallContractAmount: CurrencyText{CurrencyID: "EUR", Text: "100000"},
+					},
+				},
+			},
+			{
+				ProcurementProject: &ProcurementProject{
+					RequestedTenderTotal: &RequestedTenderTotal{
+						EstimatedOverallContractAmount: CurrencyText{CurrencyID: "USD", Text: "250000"},
+					},
+				},
+			},
+		},
+	}
+
+	amount, currency := cn.GetBudget()
+	if amount != "" || currency != "" {
+		t.Fatalf("expected no budget for mixed currencies, got amount=%q currency=%q", amount, currency)
+	}
+}

ted/mapper.go

@@ -671,17 +671,17 @@ func backfillNoticeEstimatedValueFromLots(t *notice.Notice) {
 	if t == nil || t.EstimatedValue > 0 {
 		return
 	}
-	var total float64
+	amounts := make([]valuedAmount, 0, len(t.ProcurementLots))
-	var currency string
 	for _, lot := range t.ProcurementLots {
 		if lot.EstimatedValue <= 0 {
 			continue
 		}
-		total += lot.EstimatedValue
+		amounts = append(amounts, valuedAmount{
-		if currency == "" {
+			value:    lot.EstimatedValue,
-			currency = strings.TrimSpace(lot.Currency)
+			currency: lot.Currency,
-		}
+		})
 	}
+	total, currency := aggregateSameCurrencyAmounts(amounts)
 	if total <= 0 {
 		return
 	}

ted/model.go

@@ -2003,7 +2003,7 @@ func (cn ContractNotice) GetBudget() (amount string, currency string) {
 }
 
 func budgetFromProcurementLots(lots []ProcurementProjectLot) (amount string, currency string) {
-	var total float64
+	amounts := make([]valuedAmount, 0, len(lots))
 	for i := range lots {
 		pp := lots[i].ProcurementProject
 		if pp == nil || pp.RequestedTenderTotal == nil {
@@ -2017,11 +2017,10 @@ func budgetFromProcurementLots(lots []ProcurementProjectLot) (amount string, cur
 		if !ok || value <= 0 {
 			continue
 		}
-		total += value
+		amounts = append(amounts, valuedAmount{value: value, currency: lotCurrency})
-		if currency == "" {
-			currency = lotCurrency
-		}
 	}
+
+	total, currency := aggregateSameCurrencyAmounts(amounts)
 	if total <= 0 {
 		return "", ""
 	}