added a test case for the invalid symbol replacement

store/vouchers.go

@@ -15,6 +15,11 @@ var (
 	logg = logging.NewVanilla().WithDomain("vouchers").WithContextKey("SessionId")
 )
 
+// symbolReplacements holds mappings of invalid symbols → valid ones
+var symbolReplacements = map[string]string{
+	"USD₮": "USDT",
+}
+
 // VoucherMetadata helps organize data fields
 type VoucherMetadata struct {
 	Symbols   string
@@ -23,13 +28,24 @@ type VoucherMetadata struct {
 	Addresses string
 }
 
+// sanitizeSymbol replaces known invalid token symbols with normalized ones
+func sanitizeSymbol(symbol string) string {
+	if replacement, ok := symbolReplacements[symbol]; ok {
+		return replacement
+	}
+	return symbol
+}
+
 // ProcessVouchers converts holdings into formatted strings
 func ProcessVouchers(holdings []dataserviceapi.TokenHoldings) VoucherMetadata {
 	var data VoucherMetadata
 	var symbols, balances, decimals, addresses []string
 
 	for i, h := range holdings {
-		symbols = append(symbols, fmt.Sprintf("%d:%s", i+1, h.TokenSymbol))
+		// normalize token symbol before use
+		cleanSymbol := sanitizeSymbol(h.TokenSymbol)
+
+		symbols = append(symbols, fmt.Sprintf("%d:%s", i+1, cleanSymbol))
 
 		// Scale down the balance
 		scaledBalance := ScaleDownBalance(h.Balance, h.TokenDecimals)

store/vouchers_test.go

@@ -61,13 +61,14 @@ func TestProcessVouchers(t *testing.T) {
 	holdings := []dataserviceapi.TokenHoldings{
 		{TokenAddress: "0xd4c288865Ce", TokenSymbol: "SRF", TokenDecimals: "6", Balance: "100000000"},
 		{TokenAddress: "0x41c188d63Qa", TokenSymbol: "MILO", TokenDecimals: "4", Balance: "200000000"},
+		{TokenAddress: "0x41c143d63Qa", TokenSymbol: "USD₮", TokenDecimals: "6", Balance: "300000000"},
 	}
 
 	expectedResult := VoucherMetadata{
-		Symbols:   "1:SRF\n2:MILO",
-		Balances:  "1:100\n2:20000",
-		Decimals:  "1:6\n2:4",
-		Addresses: "1:0xd4c288865Ce\n2:0x41c188d63Qa",
+		Symbols:   "1:SRF\n2:MILO\n3:USDT",
+		Balances:  "1:100\n2:20000\n3:300",
+		Decimals:  "1:6\n2:4\n3:6",
+		Addresses: "1:0xd4c288865Ce\n2:0x41c188d63Qa\n3:0x41c143d63Qa",
 	}
 
 	result := ProcessVouchers(holdings)