catcrafts.net/tests/ShouldParseEurcChains/main.cpp

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*/

// The EURC rail's two parsers.
//
// The balance decoder is the line between "the buyer paid" and "the node
// errored", and the chains parser is the line between "watching a chain"
// and "silently not watching it". Both refuse rather than guess.

import std;
import Catcrafts.Shared;
import Catcrafts.Server;

using namespace Catcrafts;

namespace {

int failures = 0;

void Check(bool ok, std::string_view what, std::string_view got = {}) {
    if (ok) return;
    ++failures;
    std::println(std::cerr, "FAIL: {}{}{}", what,
                 got.empty() ? "" : "  got: ", got);
}

} // namespace

int main() {
    using Server::ParseEthCallUint;
    Check(ParseEthCallUint(R"({"jsonrpc":"2.0","id":1,"result":"0x0"})") == 0,
          "eurc: zero balance");
    Check(ParseEthCallUint(
              R"({"jsonrpc":"2.0","id":1,"result":"0x0000000000000000000000000000000000000000000000000000000022001230"})")
              == 570430000,
          "eurc: €570.43 as 6-decimal base units, full 32-byte word");
    Check(ParseEthCallUint(R"({"result":"0xFF"})") == 255,
          "eurc: uppercase hex accepted");
    // 2^63 does not fit. It must not wrap to negative, and it must not
    // saturate to INT64_MAX either: a saturated maximum satisfies the covering
    // comparison in CheckPaid, so a node answering 0xffff…ff would mark any
    // order paid. int64 base units is already past EURC's entire supply, so an
    // unrepresentable balance is a broken or lying node — "unknown", which
    // neither settles nor lapses.
    Check(!ParseEthCallUint(R"({"result":"0x8000000000000000"})").has_value(),
          "eurc: an unrepresentable balance is unknown, not a covering maximum");
    Check(!ParseEthCallUint(
              R"({"result":"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"})")
               .has_value(),
          "eurc: a lying node's 2^256-1 does not read as paid");
    Check(!ParseEthCallUint(
              R"({"jsonrpc":"2.0","id":1,"error":{"code":-32000,"message":"x"}})")
               .has_value(),
          "eurc: an RPC error is not a zero balance");
    Check(!ParseEthCallUint(R"({"result":"21ff361c"})").has_value(),
          "eurc: missing 0x rejected");
    Check(!ParseEthCallUint(R"({"result":"0x"})").has_value(),
          "eurc: empty word rejected");
    Check(!ParseEthCallUint(R"({"result":42})").has_value(),
          "eurc: numeric result rejected — the wire type is a hex string");
    Check(!ParseEthCallUint("garbage").has_value(), "eurc: malformed payload");

    // The OUTBOUND half of the balance check, byte for byte: selector, then
    // the address left-padded into exactly one 32-byte ABI word — 24 zero hex
    // digits (12 bytes), then the 40 address digits. Pinned as a literal
    // because this line once padded 24 BYTES instead of 12: the address slid
    // past the argument word, every node cleanly answered balanceOf of a
    // zero-balance garbage address, and paid orders read as unpaid forever —
    // no error on either side. A wrong length here is money-losing even when
    // every reply parses.
    {
        const std::string data = Server::BalanceOfCallData(
            "0x311660cfd1d0c35616cf6dfc3932881b22bb46ec");
        Check(data ==
                  "0x70a08231"
                  "000000000000000000000000"
                  "311660cfd1d0c35616cf6dfc3932881b22bb46ec",
              "eurc: balanceOf calldata is selector + one 32-byte word", data);
        Check(data.size() == 2 + 8 + 64,
              "eurc: balanceOf calldata is exactly 4 + 32 bytes",
              std::to_string(data.size()));
    }

    const auto chains = Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://mainnet.base.org",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42",
         "chain_id":8453,"note":"lowest fees"},
        {"name":"ethereum","rpc":"https://ethereum-rpc.publicnode.com",
         "contract":"0x1aBaEA1f7C830bD89Acc67eC4af516284b1bC33c","chain_id":1}]})");
    Check(chains.has_value() && chains->size() == 2, "eurc: chains file parses");
    if (chains && chains->size() == 2) {
        Check((*chains)[0].name == "base" && (*chains)[0].chainId == 8453,
              "eurc: file order preserved — first entry is the recommendation");
        Check((*chains)[0].contract == "0x60a3e35cc302bfa44cb288bc5a4f316fdb1adb42",
              "eurc: contract lowercased for comparison");
        Check((*chains)[0].note == "lowest fees", "eurc: note carried");
        Check((*chains)[1].blockTag == "finalized" && (*chains)[1].decimals == 6,
              "eurc: defaults");
    }
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://x.org","contract":"0xdeadbeef"}]})").has_value(),
          "eurc: short contract rejects the whole file");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"ftp://x.org",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: non-http rpc rejects the whole file");
    Check(!Server::ParseEurcChains(R"({"chains":[]})").has_value(),
          "eurc: empty chain list rejected");
    Check(!Server::ParseEurcChains("garbage").has_value(),
          "eurc: malformed chains file rejected");

    // Two chains with one name would share a connection-map slot, so the
    // second's requests would go to the first's host and one chain would never
    // be watched at all.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://a.example",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"},
        {"name":"base","rpc":"https://b.example",
         "contract":"0x1aBaEA1f7C830bD89Acc67eC4af516284b1bC33c"}]})").has_value(),
          "eurc: duplicate chain names reject the whole file");

    // 18 decimals is legal ERC-20 but not representable here: cents × 10^16
    // overflows int64 above €9.22, and the overflow answers "unknown", which
    // neither settles nor lapses an order.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://a.example","decimals":18,
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: decimals beyond what the arithmetic carries is refused");

    // block_tag reaches the eth_call params array. A quote in it closed the
    // JSON string and appended another param; a typo silenced the chain.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://a.example","block_tag":"latest\",\"0xdead",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: a block_tag that injects JSON is refused");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://a.example","block_tag":"finalised",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: a misspelled block_tag is refused, not silently never-settling");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpc":"https://a.example","block_tag":"",
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: an empty block_tag is refused");
    {
        // A specific block number stays legitimate.
        const auto ok = Server::ParseEurcChains(R"({"chains":[
            {"name":"base","rpc":"https://a.example","block_tag":"0x1b4",
             "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})");
        Check(ok.has_value() && (*ok)[0].blockTag == "0x1b4",
              "eurc: a hex block number is still accepted");
    }

    // ── corroboration: multiple endpoints per chain ──────────────────
    {
        // The single-"rpc" shorthand still parses, and lands as one endpoint
        // with min_confirmations=1 (the pre-corroboration behaviour).
        const auto one = Server::ParseEurcChains(R"({"chains":[
            {"name":"base","rpc":"https://a.example",
             "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})");
        Check(one.has_value() && (*one)[0].rpcUrls.size() == 1
                  && (*one)[0].rpcUrls[0] == "https://a.example"
                  && (*one)[0].minConfirmations == 1,
              "eurc: the single-rpc shorthand still loads, one source, one confirmation");

        // Two endpoints default to requiring agreement between both.
        const auto two = Server::ParseEurcChains(R"({"chains":[
            {"name":"base","rpcs":["https://a.example","https://b.example"],
             "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})");
        Check(two.has_value() && (*two)[0].rpcUrls.size() == 2
                  && (*two)[0].minConfirmations == 2,
              "eurc: two endpoints default to two confirmations");

        // Three endpoints still default to two — a quorum, not unanimity, so
        // one node being down does not stop the shop settling.
        const auto three = Server::ParseEurcChains(R"({"chains":[
            {"name":"base","rpcs":["https://a.example","https://b.example",
                                   "https://c.example"],
             "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})");
        Check(three.has_value() && (*three)[0].minConfirmations == 2,
              "eurc: three endpoints still need two agreeing, not all three");

        // An explicit value is honoured.
        const auto strict = Server::ParseEurcChains(R"({"chains":[
            {"name":"base","rpcs":["https://a.example","https://b.example",
                                   "https://c.example"],"min_confirmations":3,
             "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})");
        Check(strict.has_value() && (*strict)[0].minConfirmations == 3,
              "eurc: an explicit min_confirmations is honoured");
    }

    // One endpoint cannot corroborate itself, so a repeated URL is refused
    // rather than counted twice toward the quorum.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":["https://a.example","https://a.example"],
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: the same endpoint listed twice is refused");

    // Asking for more agreement than there are sources would never settle
    // anything — a silent never-pays shop, so it is a refusal at load.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":["https://a.example","https://b.example"],
         "min_confirmations":3,
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: more confirmations than endpoints is refused");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":["https://a.example"],"min_confirmations":0,
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: zero confirmations is refused");

    // An empty rpcs list is not a chain that can be watched.
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":[],
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: an empty endpoint list is refused");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":["https://a.example",42],
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: a non-string endpoint is refused");
    Check(!Server::ParseEurcChains(R"({"chains":[
        {"name":"base","rpcs":["https://a.example","ftp://b.example"],
         "contract":"0x60a3E35Cc302bFA44Cb288Bc5a4F316Fdb1adb42"}]})").has_value(),
          "eurc: a non-http endpoint anywhere in the list is refused");

    if (failures != 0) {
        std::println(std::cerr, "{} check(s) failed", failures);
        return 1;
    }
    return 0;
}