fix(gcp/cloudstorage): apply the currency unification to the Cloud Storage extractor

providers/gcp/services/cloudstorage/client.go

@@ -13,6 +13,7 @@ import (
 	"google.golang.org/api/option"
 
 	"github.com/LeanerCloud/cloud-commitments-go/pkg/common"
+	"github.com/LeanerCloud/cloud-commitments-go/providers/gcp/internal/billingcurrency"
 	"github.com/LeanerCloud/cloud-commitments-go/providers/gcp/internal/skulist"
 	"github.com/LeanerCloud/cloud-commitments-go/providers/gcp/internal/skumatch"
 )
@@ -280,8 +281,6 @@ func (c *Client) getOrCreateBillingService(ctx context.Context) (BillingService,
 
 // extractStoragePricingFromSKUs extracts on-demand and commitment pricing from SKU list.
 func extractStoragePricingFromSKUs(skus []*cloudbilling.Sku, storageClass, region string) (onDemand, commitment float64, currency string, err error) {
-	currency = "USD"
-
 	for _, sku := range skus {
 		if !skuMatchesStorageClass(sku, storageClass, region) {
 			continue
@@ -295,8 +294,9 @@ func extractStoragePricingFromSKUs(skus []*cloudbilling.Sku, storageClass, regio
 			continue
 		}
 
-		if curr != "" {
-			currency = curr
+		currency, err = billingcurrency.Unify(currency, curr, sku.SkuId)
+		if err != nil {
+			return 0, 0, "", err
 		}
 
 		slot, slotErr := skumatch.Slot(sku)

providers/gcp/services/cloudstorage/pricing_currency_test.go

@@ -0,0 +1,64 @@
+package cloudstorage
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/api/cloudbilling/v1"
+)
+
+func currencySKU(id, description, usageType, region, currency string, nanos int64) *cloudbilling.Sku {
+	return &cloudbilling.Sku{
+		SkuId:          id,
+		Description:    description,
+		Category:       &cloudbilling.Category{UsageType: usageType},
+		ServiceRegions: []string{region},
+		PricingInfo: []*cloudbilling.PricingInfo{{
+			PricingExpression: &cloudbilling.PricingExpression{
+				UsageUnit: "GiBy.mo",
+				TieredRates: []*cloudbilling.TierRate{{
+					UnitPrice: &cloudbilling.Money{CurrencyCode: currency, Nanos: nanos},
+				}},
+			},
+		}},
+	}
+}
+
+func TestGetStoragePricing_Currency(t *testing.T) {
+	const storageClass, region = "STANDARD", "us-central1"
+	tests := []struct {
+		name         string
+		onDemandCur  string
+		commitCur    string
+		wantCurrency string
+		wantErr      string
+	}{
+		{name: "consistent non-USD currency is returned as is", onDemandCur: "EUR", commitCur: "EUR", wantCurrency: "EUR"},
+		{name: "consistent USD", onDemandCur: "USD", commitCur: "USD", wantCurrency: "USD"},
+		{name: "on-demand and commitment currencies differ", onDemandCur: "USD", commitCur: "EUR", wantErr: "priced in EUR but earlier SKUs are priced in USD"},
+		{name: "commitment currency missing", onDemandCur: "EUR", commitCur: "", wantErr: "no currency code"},
+		{name: "on-demand currency missing", onDemandCur: "", commitCur: "EUR", wantErr: "no currency code"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
+			client, err := NewClient(ctx, "test-project", region)
+			require.NoError(t, err)
+			client.SetBillingService(&MockBillingService{skus: &cloudbilling.ListSkusResponse{Skus: []*cloudbilling.Sku{
+				currencySKU("od", storageClass+" Storage in "+region, "OnDemand", region, tt.onDemandCur, 26000000),
+				currencySKU("cud", storageClass+" Storage commitment in "+region, "Commit1Yr", region, tt.commitCur, 19500000),
+			}}})
+
+			got, err := client.getStoragePricing(ctx, storageClass, region, 1)
+			if tt.wantErr != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tt.wantErr)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tt.wantCurrency, got.Currency)
+		})
+	}
+}