unit test server fails for bad error reponse test case about libmodbus HOT 3 CLOSED

Which loop? Could you send me your modified code?
Do you use the new the tarball for v2.9.3?

from libmodbus.

I have used the tarball v2.9.3. To pass all the test cases, I have modified for loop in the unit-test-server.c to flush data. please find the snippet of code for reference, i have also marked "modbus_flush" function in bold.

for (;;) {
rc = modbus_receive(ctx, -1, query);
if (rc == -1) {
/* Connection closed by the client or error */
break;
}

    /* Read holding registers */
    if (query[header_length] == 0x03) {
        if (MODBUS_GET_INT16_FROM_INT8(query, header_length + 3)
            == UT_REGISTERS_NB_POINTS_SPECIAL) {
            printf("Set an incorrect number of values\n");
            MODBUS_SET_INT16_TO_INT8(query, header_length + 3,
                                     UT_REGISTERS_NB_POINTS);
        } else if (MODBUS_GET_INT16_FROM_INT8(query, header_length + 1)
            == UT_REGISTERS_ADDRESS_SPECIAL) {
            modbus_reply_exception(ctx, query,
                                   MODBUS_EXCEPTION_SLAVE_OR_SERVER_BUSY);
            continue;
        }
    }

    rc = modbus_reply(ctx, query, rc, mb_mapping);
    if (rc == -1) {
        break;
    }

    modbus_flush(ctx);

• Hide quoted text -
  }

from libmodbus.

OK, it's just a workaround but unit tests contain many strange things on purpose so I don't want to hide them with this call.
I don't have the problem on my computer so could you post at least 25 lines of history of server/client tests (github offers a pastebin like). Did you use TCP tests on localhost?

from libmodbus.