Reported here: https://github.com/bitcoin/bitcoin/pull/10244#issuecomment-378035305

Travis log here: https://travis-ci.org/bitcoin/bitcoin/jobs/361243719#L2810

Note the JSON exception:

```
test_framework.authproxy.JSONRPCException: The mempool was not loaded yet (-1) 
```

That exception was introduced here: https://github.com/bitcoin/bitcoin/commit/cb1e319fe9e198c9c5cf5236fe9af5a3d748b9e8#diff-a0c8f511d90e83aa9b5857e819ced344R1617

cc @jtimon 
{
    if (request.fHelp || request.params.size() != 0)
        throw std::runtime_error(
            RPCHelpMan{"gettxoutsetinfo",
                "\nReturns statistics about the unspent transaction output set.\n"
                "Note this call may take some time.\n",
                {},
                RPCResult{
            "{\n"
            "  \"height\":n,     (numeric) The current block height (index)\n"
            "  \"bestblock\": \"hex\",   (string) The hash of the block at the tip of the chain\n"
            "  \"transactions\": n,      (numeric) The number of transactions with unspent outputs\n"
            "  \"txouts\": n,            (numeric) The number of unspent transaction outputs\n"
            "  \"bogosize\": n,          (numeric) A meaningless metric for UTXO set size\n"
            "  \"hash_serialized_2\": \"hash\", (string) The serialized hash\n"
            "  \"disk_size\": n,         (numeric) The estimated size of the chainstate on disk\n"
            "  \"total_amount\": x.xxx          (numeric) The total amount\n"
            "}\n"
                },
                RPCExamples{
                    HelpExampleCli("gettxoutsetinfo", "")
            + HelpExampleRpc("gettxoutsetinfo", "")
                },
            }.ToString());