Add new formatting regex

rpc/responses_test.go

@@ -17,7 +17,8 @@ const (
 	reHashOpt    = `"(0x[0-9a-f]{64})"|null`             // 32 bytes or null
 	reAddress    = `"0x[0-9a-f]{40}"`                    // 20 bytes
 	reAddressOpt = `"0x[0-9a-f]{40}"|null`               // 20 bytes or null
-	reNum        = `"0x([1-9a-f][0-9a-f]{1,15})|0"` // must not have left-padded zeros
+	reNum        = `"0x([1-9a-f][0-9a-f]{0,15})|0"`      // must not have left-padded zeros
+	reNumOpt     = `"0x([1-9a-f][0-9a-f]{0,15})|0"|null` // must not have left-padded zeros or null
 	reData       = `"0x[0-9a-f]*"`                       // can be "empty"
 )