production runtime and mock removal

backend/internal/billing/catalog.go

@@ -12,9 +12,10 @@ import (
 const CurrencyCNY = "CNY"
 
 var (
-	ErrAmbiguousPriceRule = errors.New("billing price rules are ambiguous")
-	ErrPriceRuleNotFound  = errors.New("billing price rule not found")
-	ErrParameterTier      = errors.New("billing parameter tier not found")
+	ErrAmbiguousPriceRule  = errors.New("billing price rules are ambiguous")
+	ErrPriceRuleNotFound   = errors.New("billing price rule not found")
+	ErrParameterTier       = errors.New("billing parameter tier not found")
+	ErrProviderUnavailable = errors.New("billing provider is unavailable")
 )
 
 type Unit string
@@ -103,9 +104,12 @@ type Quote struct {
 type Catalog struct{ Rules []PriceRule }
 
 func (c Catalog) Quote(input QuoteInput) (*Quote, error) {
-	if input.BillingDisabled || input.Provider == "mock" {
+	if input.BillingDisabled {
 		return nil, nil
 	}
+	if input.Provider == "mock" {
+		return nil, ErrProviderUnavailable
+	}
 	type candidate struct {
 		rule                      PriceRule
 		req, conditions, priority int