payment tests

server/interfaces/Catcrafts.Server.cppm

@@ -410,6 +410,16 @@ export namespace Catcrafts::Server {
     // the HTTP around it is thin.
     std::optional<std::int64_t> ParseEthCallUint(std::string_view json);
 
+    // The eth_call data for balanceOf(address): the 4-byte selector, then the
+    // address left-padded into ONE 32-byte ABI word. Exported for the
+    // self-test for the same reason as ParseEthCallUint, learned the hard
+    // way: this encoding once padded 24 zero bytes instead of 12 (a
+    // bytes-vs-hex-digits slip), which pushed the address out of the argument
+    // word — every node then answered balanceOf of a zero-balance garbage
+    // address, cleanly, and paid orders read as unpaid forever. No error
+    // anywhere; the testnet e2e suite is what caught it.
+    std::string BalanceOfCallData(std::string_view address);
+
     // nullptr when the chains file or the address pool will not load. The rail
     // holds no key and no credential; it can only ever hand out an address it
     // was given.