path: root/src/lib/test_merchant_api.c

/*
  This file is part of TALER
  Copyright (C) 2014, 2015, 2016 GNUnet e.V. and INRIA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file merchant/test_merchant_api.c
 * @brief testcase to test merchant's HTTP API interface
 * @author Christian Grothoff
 */
#include "platform.h"
#include <taler/taler_util.h>
#include <taler/taler_signatures.h>
#include <taler/taler_exchange_service.h>
#include "taler_merchant_service.h"
#include <gnunet/gnunet_util_lib.h>
#include <microhttpd.h>

/**
 * URI under which the merchant is reachable during the testcase.
 */
#define MERCHANT_URI "http://localhost:8082/"

/**
 * URI under which the exchange is reachable during the testcase.
 */
#define EXCHANGE_URI "http://localhost:8081/"

/**
 * Main execution context for the main loop of the exchange.
 */
static struct TALER_EXCHANGE_Context *ctx;

/**
 * Handle to access the exchange.
 */
static struct TALER_EXCHANGE_Handle *exchange;

/**
 * Main execution context for the main loop of the exchange.
 */
static struct TALER_MERCHANT_Context *merchant;

/**
 * Public key of the merchant, matches the private
 * key from "test_merchant.priv".
 */
static struct TALER_MerchantPublicKeyP merchant_pub;

/**
 * Task run on shutdown.
 */
static struct GNUNET_SCHEDULER_Task *shutdown_task;

/**
 * Task that runs the main event loop.
 */
static struct GNUNET_SCHEDULER_Task *ctx_task;

/**
 * Result of the testcases, #GNUNET_OK on success
 */
static int result;


/**
 * Opcodes for the interpreter.
 */
enum OpCode
{
  /**
   * Termination code, stops the interpreter loop (with success).
   */
  OC_END = 0,

  /**
   * Add funds to a reserve by (faking) incoming wire transfer.
   */
  OC_ADMIN_ADD_INCOMING,

  /**
   * Check status of a reserve.
   */
  OC_WITHDRAW_STATUS,

  /**
   * Withdraw a coin from a reserve.
   */
  OC_WITHDRAW_SIGN,

  /**
   * Pay with coins.
   */
  OC_PAY

};


/**
 * Structure specifying details about a coin to be melted.
 * Used in a NULL-terminated array as part of command
 * specification.
 */
struct MeltDetails
{

  /**
   * Amount to melt (including fee).
   */
  const char *amount;

  /**
   * Reference to reserve_withdraw operations for coin to
   * be used for the /refresh/melt operation.
   */
  const char *coin_ref;

};


/**
 * Information about a fresh coin generated by the refresh operation.
 */
struct FreshCoin
{

  /**
   * If @e amount is NULL, this specifies the denomination key to
   * use.  Otherwise, this will be set (by the interpreter) to the
   * denomination PK matching @e amount.
   */
  const struct TALER_EXCHANGE_DenomPublicKey *pk;

  /**
   * Set (by the interpreter) to the exchange's signature over the
   * coin's public key.
   */
  struct TALER_DenominationSignature sig;

  /**
   * Set (by the interpreter) to the coin's private key.
   */
  struct TALER_CoinSpendPrivateKeyP coin_priv;

};


/**
 * Details for a exchange operation to execute.
 */
struct Command
{
  /**
   * Opcode of the command.
   */
  enum OpCode oc;

  /**
   * Label for the command, can be NULL.
   */
  const char *label;

  /**
   * Which response code do we expect for this command?
   */
  unsigned int expected_response_code;

  /**
   * Details about the command.
   */
  union
  {

    /**
     * Information for a #OC_ADMIN_ADD_INCOMING command.
     */
    struct
    {

      /**
       * Label to another admin_add_incoming command if we
       * should deposit into an existing reserve, NULL if
       * a fresh reserve should be created.
       */
      const char *reserve_reference;

      /**
       * String describing the amount to add to the reserve.
       */
      const char *amount;

      /**
       * Wire details (JSON).
       */
      const char *wire;

      /**
       * Set (by the interpreter) to the reserve's private key
       * we used to fill the reserve.
       */
      struct TALER_ReservePrivateKeyP reserve_priv;

      /**
       * Set to the API's handle during the operation.
       */
      struct TALER_EXCHANGE_AdminAddIncomingHandle *aih;

    } admin_add_incoming;

    /**
     * Information for a #OC_WITHDRAW_STATUS command.
     */
    struct
    {

      /**
       * Label to the #OC_ADMIN_ADD_INCOMING command which
       * created the reserve.
       */
      const char *reserve_reference;

      /**
       * Set to the API's handle during the operation.
       */
      struct TALER_EXCHANGE_ReserveStatusHandle *wsh;

      /**
       * Expected reserve balance.
       */
      const char *expected_balance;

    } reserve_status;

    /**
     * Information for a #OC_WITHDRAW_SIGN command.
     */
    struct
    {

      /**
       * Which reserve should we withdraw from?
       */
      const char *reserve_reference;

      /**
       * String describing the denomination value we should withdraw.
       * A corresponding denomination key must exist in the exchange's
       * offerings.  Can be NULL if @e pk is set instead.
       */
      const char *amount;

      /**
       * If @e amount is NULL, this specifies the denomination key to
       * use.  Otherwise, this will be set (by the interpreter) to the
       * denomination PK matching @e amount.
       */
      const struct TALER_EXCHANGE_DenomPublicKey *pk;

      /**
       * Set (by the interpreter) to the exchange's signature over the
       * coin's public key.
       */
      struct TALER_DenominationSignature sig;

      /**
       * Set (by the interpreter) to the coin's private key.
       */
      struct TALER_CoinSpendPrivateKeyP coin_priv;

      /**
       * Blinding key used for the operation.
       */
      struct TALER_DenominationBlindingKey blinding_key;

      /**
       * Withdraw handle (while operation is running).
       */
      struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh;

    } reserve_withdraw;

    /**
     * Information for a #OC_PAY command.
     * FIXME: support tests where we pay with multiple coins at once.
     */
    struct
    {

      /**
       * Amount to pay (total for the entire contract).
       */
      const char *total_amount;

      /**
       * Maximum fee covered by merchant.
       */
      const char *max_fee;

      /**
       * Reference to a reserve_withdraw operation for a coin to
       * be used for the /deposit operation.
       */
      const char *coin_ref;

      /**
       * If this @e coin_ref refers to an operation that generated
       * an array of coins, this value determines which coin to use.
       */
      unsigned int coin_idx;

      /**
       * Amount to pay (from the coin, including fee).
       */
      const char *amount_with_fee;

      /**
       * Amount to pay (from the coin, excluding fee).  The sum of the
       * deltas between all @e amount_with_fee and the @e
       * amount_without_fee must be less than max_fee, and the sum of
       * the @e amount_with_fee must be larger than the @e
       * total_amount.
       */
      const char *amount_without_fee;

      /**
       * JSON string describing the merchant's "wire details".
       */
      const char *wire_details;

      /**
       * JSON string describing the contract between the two parties.
       */
      const char *contract;

      /**
       * Transaction ID to use.
       */
      uint64_t transaction_id;

      /**
       * Relative time (to add to 'now') to compute the refund deadline.
       * Zero for no refunds.
       */
      struct GNUNET_TIME_Relative refund_deadline;

      /**
       * Deposit handle while operation is running.
       */
      struct TALER_MERCHANT_Pay *ph;

    } pay;

  } details;

};


/**
 * State of the interpreter loop.
 */
struct InterpreterState
{
  /**
   * Keys from the exchange.
   */
  const struct TALER_EXCHANGE_Keys *keys;

  /**
   * Commands the interpreter will run.
   */
  struct Command *commands;

  /**
   * Interpreter task (if one is scheduled).
   */
  struct GNUNET_SCHEDULER_Task *task;

  /**
   * Instruction pointer.  Tells #interpreter_run() which
   * instruction to run next.
   */
  unsigned int ip;

};


/**
 * Task that runs the context's event loop with the GNUnet scheduler.
 *
 * @param cls unused
 * @param tc scheduler context (unused)
 */
static void
context_task (void *cls,
              const struct GNUNET_SCHEDULER_TaskContext *tc);


/**
 * Run the context task, the working set has changed.
 */
static void
trigger_context_task ()
{
  GNUNET_SCHEDULER_cancel (ctx_task);
  ctx_task = GNUNET_SCHEDULER_add_now (&context_task,
                                       NULL);
}


/**
 * The testcase failed, return with an error code.
 *
 * @param is interpreter state to clean up
 */
static void
fail (struct InterpreterState *is)
{
  result = GNUNET_SYSERR;
  GNUNET_SCHEDULER_shutdown ();
}


/**
 * Find a command by label.
 *
 * @param is interpreter state to search
 * @param label label to look for
 * @return NULL if command was not found
 */
static const struct Command *
find_command (const struct InterpreterState *is,
              const char *label)
{
  unsigned int i;
  const struct Command *cmd;

  if (NULL == label)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Attempt to lookup command for empty label\n");
    return NULL;
  }
  for (i=0;OC_END != (cmd = &is->commands[i])->oc;i++)
    if ( (NULL != cmd->label) &&
         (0 == strcmp (cmd->label,
                       label)) )
      return cmd;
  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
              "Command not found: %s\n",
              label);
  return NULL;
}


/**
 * Run the main interpreter loop that performs exchange operations.
 *
 * @param cls contains the `struct InterpreterState`
 * @param tc scheduler context
 */
static void
interpreter_run (void *cls,
                 const struct GNUNET_SCHEDULER_TaskContext *tc);


/**
 * Function called upon completion of our /admin/add/incoming request.
 *
 * @param cls closure with the interpreter state
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
 *                    0 if the exchange's reply is bogus (fails to follow the protocol)
 * @param full_response full response from the exchange (for logging, in case of errors)
 */
static void
add_incoming_cb (void *cls,
                 unsigned int http_status,
                 json_t *full_response)
{
  struct InterpreterState *is = cls;
  struct Command *cmd = &is->commands[is->ip];

  cmd->details.admin_add_incoming.aih = NULL;
  if (MHD_HTTP_OK != http_status)
  {
    GNUNET_break (0);
    fail (is);
    return;
  }
  is->ip++;
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Check if the given historic event @a h corresponds to the given
 * command @a cmd.
 *
 * @param h event in history
 * @param cmd an #OC_ADMIN_ADD_INCOMING command
 * @return #GNUNET_OK if they match, #GNUNET_SYSERR if not
 */
static int
compare_admin_add_incoming_history (const struct TALER_EXCHANGE_ReserveHistory *h,
                                    const struct Command *cmd)
{
  struct TALER_Amount amount;

  if (TALER_EXCHANGE_RTT_DEPOSIT != h->type)
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  GNUNET_assert (GNUNET_OK ==
                 TALER_string_to_amount (cmd->details.admin_add_incoming.amount,
                                         &amount));
  if (0 != TALER_amount_cmp (&amount,
                             &h->amount))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Check if the given historic event @a h corresponds to the given
 * command @a cmd.
 *
 * @param h event in history
 * @param cmd an #OC_WITHDRAW_SIGN command
 * @return #GNUNET_OK if they match, #GNUNET_SYSERR if not
 */
static int
compare_reserve_withdraw_history (const struct TALER_EXCHANGE_ReserveHistory *h,
                                  const struct Command *cmd)
{
  struct TALER_Amount amount;
  struct TALER_Amount amount_with_fee;

  if (TALER_EXCHANGE_RTT_WITHDRAWAL != h->type)
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  GNUNET_assert (GNUNET_OK ==
                 TALER_string_to_amount (cmd->details.reserve_withdraw.amount,
                                         &amount));
  GNUNET_assert (GNUNET_OK ==
                 TALER_amount_add (&amount_with_fee,
                                   &amount,
                                   &cmd->details.reserve_withdraw.pk->fee_withdraw));
  if (0 != TALER_amount_cmp (&amount_with_fee,
                             &h->amount))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


/**
 * Function called with the result of a /reserve/status request.
 *
 * @param cls closure with the interpreter state
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
 *                    0 if the exchange's reply is bogus (fails to follow the protocol)
 * @param[in] json original response in JSON format (useful only for diagnostics)
 * @param balance current balance in the reserve, NULL on error
 * @param history_length number of entries in the transaction history, 0 on error
 * @param history detailed transaction history, NULL on error
 */
static void
reserve_status_cb (void *cls,
                   unsigned int http_status,
                   json_t *json,
                   const struct TALER_Amount *balance,
                   unsigned int history_length,
                   const struct TALER_EXCHANGE_ReserveHistory *history)
{
  struct InterpreterState *is = cls;
  struct Command *cmd = &is->commands[is->ip];
  struct Command *rel;
  unsigned int i;
  unsigned int j;
  struct TALER_Amount amount;

  cmd->details.reserve_status.wsh = NULL;
  if (cmd->expected_response_code != http_status)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u to command %s\n",
                http_status,
                cmd->label);
    GNUNET_break (0);
    json_dumpf (json, stderr, 0);
    fail (is);
    return;
  }
  switch (http_status)
  {
  case MHD_HTTP_OK:
    j = 0;
    for (i=0;i<is->ip;i++)
    {
      switch ((rel = &is->commands[i])->oc)
      {
      case OC_ADMIN_ADD_INCOMING:
        if ( ( (NULL != rel->label) &&
               (0 == strcmp (cmd->details.reserve_status.reserve_reference,
                             rel->label) ) ) ||
             ( (NULL != rel->details.admin_add_incoming.reserve_reference) &&
               (0 == strcmp (cmd->details.reserve_status.reserve_reference,
                             rel->details.admin_add_incoming.reserve_reference) ) ) )
        {
          if (GNUNET_OK !=
              compare_admin_add_incoming_history (&history[j],
                                                  rel))
          {
            GNUNET_break (0);
            fail (is);
            return;
          }
          j++;
        }
        break;
      case OC_WITHDRAW_SIGN:
        if (0 == strcmp (cmd->details.reserve_status.reserve_reference,
                         rel->details.reserve_withdraw.reserve_reference))
        {
          if (GNUNET_OK !=
              compare_reserve_withdraw_history (&history[j],
                                             rel))
          {
            GNUNET_break (0);
            fail (is);
            return;
          }
          j++;
        }
        break;
      default:
        /* unreleated, just skip */
        break;
      }
    }
    if (j != history_length)
    {
      GNUNET_break (0);
      fail (is);
      return;
    }
    if (NULL != cmd->details.reserve_status.expected_balance)
    {
      GNUNET_assert (GNUNET_OK ==
                     TALER_string_to_amount (cmd->details.reserve_status.expected_balance,
                                             &amount));
      if (0 != TALER_amount_cmp (&amount,
                                 balance))
      {
        GNUNET_break (0);
        fail (is);
        return;
      }
    }
    break;
  default:
    /* Unsupported status code (by test harness) */
    GNUNET_break (0);
    break;
  }
  is->ip++;
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Function called upon completion of our /reserve/withdraw request.
 *
 * @param cls closure with the interpreter state
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful status request
 *                    0 if the exchange's reply is bogus (fails to follow the protocol)
 * @param sig signature over the coin, NULL on error
 * @param full_response full response from the exchange (for logging, in case of errors)
 */
static void
reserve_withdraw_cb (void *cls,
                     unsigned int http_status,
                     const struct TALER_DenominationSignature *sig,
                     json_t *full_response)
{
  struct InterpreterState *is = cls;
  struct Command *cmd = &is->commands[is->ip];

  cmd->details.reserve_withdraw.wsh = NULL;
  if (cmd->expected_response_code != http_status)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u to command %s\n",
                http_status,
                cmd->label);
    json_dumpf (full_response, stderr, 0);
    GNUNET_break (0);
    fail (is);
    return;
  }
  switch (http_status)
  {
  case MHD_HTTP_OK:
    if (NULL == sig)
    {
      GNUNET_break (0);
      fail (is);
      return;
    }
    cmd->details.reserve_withdraw.sig.rsa_signature
      = GNUNET_CRYPTO_rsa_signature_dup (sig->rsa_signature);
    break;
  case MHD_HTTP_PAYMENT_REQUIRED:
    /* nothing to check */
    break;
  default:
    /* Unsupported status code (by test harness) */
    GNUNET_break (0);
    break;
  }
  is->ip++;
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Function called with the result of a /pay operation.
 *
 * @param cls closure with the interpreter state
 * @param http_status HTTP response code, #MHD_HTTP_OK (200) for successful deposit;
 *                    0 if the exchange's reply is bogus (fails to follow the protocol)
 * @param obj the received JSON reply, should be kept as proof (and, in case of errors,
 *            be forwarded to the customer)
 */
static void
pay_cb (void *cls,
        unsigned int http_status,
        const char *redirect_uri,
        json_t *obj)
{
  struct InterpreterState *is = cls;
  struct Command *cmd = &is->commands[is->ip];

  cmd->details.pay.ph = NULL;
  if (cmd->expected_response_code != http_status)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u to command %s\n",
                http_status,
                cmd->label);
    json_dumpf (obj, stderr, 0);
    fail (is);
    return;
  }
  is->ip++;
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Find denomination key matching the given amount.
 *
 * @param keys array of keys to search
 * @param amount coin value to look for
 * @return NULL if no matching key was found
 */
static const struct TALER_EXCHANGE_DenomPublicKey *
find_pk (const struct TALER_EXCHANGE_Keys *keys,
         const struct TALER_Amount *amount)
{
  unsigned int i;
  struct GNUNET_TIME_Absolute now;
  struct TALER_EXCHANGE_DenomPublicKey *pk;
  char *str;

  now = GNUNET_TIME_absolute_get ();
  for (i=0;i<keys->num_denom_keys;i++)
  {
    pk = &keys->denom_keys[i];
    if ( (0 == TALER_amount_cmp (amount,
                                 &pk->value)) &&
         (now.abs_value_us >= pk->valid_from.abs_value_us) &&
         (now.abs_value_us < pk->withdraw_valid_until.abs_value_us) )
      return pk;
  }
  /* do 2nd pass to check if expiration times are to blame for failure */
  str = TALER_amount_to_string (amount);
  for (i=0;i<keys->num_denom_keys;i++)
  {
    pk = &keys->denom_keys[i];
    if ( (0 == TALER_amount_cmp (amount,
                                 &pk->value)) &&
         ( (now.abs_value_us < pk->valid_from.abs_value_us) ||
           (now.abs_value_us > pk->withdraw_valid_until.abs_value_us) ) )
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Have denomination key for `%s', but with wrong expiration range %llu vs [%llu,%llu)\n",
                  str,
                  now.abs_value_us,
                  pk->valid_from.abs_value_us,
                  pk->withdraw_valid_until.abs_value_us);
      GNUNET_free (str);
      return NULL;
    }
  }
  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
              "No denomination key for amount %s found\n",
              str);
  GNUNET_free (str);
  return NULL;
}


/**
 * Run the main interpreter loop that performs exchange operations.
 *
 * @param cls contains the `struct InterpreterState`
 * @param tc scheduler context
 */
static void
interpreter_run (void *cls,
                 const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct InterpreterState *is = cls;
  struct Command *cmd = &is->commands[is->ip];
  const struct Command *ref;
  struct TALER_ReservePublicKeyP reserve_pub;
  struct TALER_CoinSpendPublicKeyP coin_pub;
  struct TALER_Amount amount;
  struct GNUNET_TIME_Absolute execution_date;
  json_t *wire;

  is->task = NULL;
  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
  {
    fprintf (stderr,
             "Test aborted by shutdown request\n");
    fail (is);
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Interpreter runs command %u/%s(%u)\n",
	      is->ip,
	      cmd->label,
	      cmd->oc);
  switch (cmd->oc)
  {
  case OC_END:
    result = GNUNET_OK;
    GNUNET_SCHEDULER_shutdown ();
    return;
  case OC_ADMIN_ADD_INCOMING:
    if (NULL !=
        cmd->details.admin_add_incoming.reserve_reference)
    {
      ref = find_command (is,
                          cmd->details.admin_add_incoming.reserve_reference);
      GNUNET_assert (NULL != ref);
      GNUNET_assert (OC_ADMIN_ADD_INCOMING == ref->oc);
      cmd->details.admin_add_incoming.reserve_priv
        = ref->details.admin_add_incoming.reserve_priv;
    }
    else
    {
      struct GNUNET_CRYPTO_EddsaPrivateKey *priv;

      priv = GNUNET_CRYPTO_eddsa_key_create ();
      cmd->details.admin_add_incoming.reserve_priv.eddsa_priv = *priv;
      GNUNET_free (priv);
    }
    GNUNET_CRYPTO_eddsa_key_get_public (&cmd->details.admin_add_incoming.reserve_priv.eddsa_priv,
                                        &reserve_pub.eddsa_pub);
    if (GNUNET_OK !=
        TALER_string_to_amount (cmd->details.admin_add_incoming.amount,
                                &amount))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Failed to parse amount `%s' at %u\n",
                  cmd->details.admin_add_incoming.amount,
                  is->ip);
      fail (is);
      return;
    }
    wire = json_loads (cmd->details.admin_add_incoming.wire,
                       JSON_REJECT_DUPLICATES,
                       NULL);
    if (NULL == wire)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Failed to parse wire details `%s' at %u\n",
                  cmd->details.admin_add_incoming.wire,
                  is->ip);
      fail (is);
      return;
    }
    execution_date = GNUNET_TIME_absolute_get ();
    TALER_round_abs_time (&execution_date);
    cmd->details.admin_add_incoming.aih
      = TALER_EXCHANGE_admin_add_incoming (exchange,
                                       &reserve_pub,
                                       &amount,
                                       execution_date,
                                       wire,
                                       &add_incoming_cb,
                                       is);
    if (NULL == cmd->details.admin_add_incoming.aih)
    {
      GNUNET_break (0);
      fail (is);
      return;
    }
    trigger_context_task ();
    return;
  case OC_WITHDRAW_STATUS:
    GNUNET_assert (NULL !=
                   cmd->details.reserve_status.reserve_reference);
    ref = find_command (is,
                        cmd->details.reserve_status.reserve_reference);
    GNUNET_assert (NULL != ref);
    GNUNET_assert (OC_ADMIN_ADD_INCOMING == ref->oc);
    GNUNET_CRYPTO_eddsa_key_get_public (&ref->details.admin_add_incoming.reserve_priv.eddsa_priv,
                                        &reserve_pub.eddsa_pub);
    cmd->details.reserve_status.wsh
      = TALER_EXCHANGE_reserve_status (exchange,
                                   &reserve_pub,
                                   &reserve_status_cb,
                                   is);
    trigger_context_task ();
    return;
  case OC_WITHDRAW_SIGN:
    GNUNET_assert (NULL !=
                   cmd->details.reserve_withdraw.reserve_reference);
    ref = find_command (is,
                        cmd->details.reserve_withdraw.reserve_reference);
    GNUNET_assert (NULL != ref);
    GNUNET_assert (OC_ADMIN_ADD_INCOMING == ref->oc);
    if (NULL != cmd->details.reserve_withdraw.amount)
    {
      if (GNUNET_OK !=
          TALER_string_to_amount (cmd->details.reserve_withdraw.amount,
                                  &amount))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    "Failed to parse amount `%s' at %u\n",
                    cmd->details.reserve_withdraw.amount,
                    is->ip);
        fail (is);
        return;
      }
      cmd->details.reserve_withdraw.pk = find_pk (is->keys,
                                                  &amount);
    }
    if (NULL == cmd->details.reserve_withdraw.pk)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Failed to determine denomination key at %u\n",
                  is->ip);
      fail (is);
      return;
    }

    /* create coin's private key */
    {
      struct GNUNET_CRYPTO_EddsaPrivateKey *priv;

      priv = GNUNET_CRYPTO_eddsa_key_create ();
      cmd->details.reserve_withdraw.coin_priv.eddsa_priv = *priv;
      GNUNET_free (priv);
    }
    GNUNET_CRYPTO_eddsa_key_get_public (&cmd->details.reserve_withdraw.coin_priv.eddsa_priv,
                                        &coin_pub.eddsa_pub);
    cmd->details.reserve_withdraw.blinding_key.rsa_blinding_key
      = GNUNET_CRYPTO_rsa_blinding_key_create (GNUNET_CRYPTO_rsa_public_key_len (cmd->details.reserve_withdraw.pk->key.rsa_public_key));
    cmd->details.reserve_withdraw.wsh
      = TALER_EXCHANGE_reserve_withdraw (exchange,
                                     cmd->details.reserve_withdraw.pk,
                                     &ref->details.admin_add_incoming.reserve_priv,
                                     &cmd->details.reserve_withdraw.coin_priv,
                                     &cmd->details.reserve_withdraw.blinding_key,
                                     &reserve_withdraw_cb,
                                     is);
    if (NULL == cmd->details.reserve_withdraw.wsh)
    {
      GNUNET_break (0);
      fail (is);
      return;
    }
    trigger_context_task ();
    return;
  case OC_PAY:
    {
      struct TALER_MERCHANT_PayCoin pc;
      struct TALER_Amount amount;
      struct TALER_Amount max_fee;
      json_t *wire;
      json_t *contract;
      struct GNUNET_HashCode h_wire;
      struct GNUNET_HashCode h_contract;
      struct GNUNET_TIME_Absolute refund_deadline;
      struct GNUNET_TIME_Absolute timestamp;

      /* get amount */
      if (GNUNET_OK !=
	  TALER_string_to_amount (cmd->details.pay.total_amount,
				  &amount))
      {
	GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		    "Failed to parse total amount `%s' at %u\n",
		    cmd->details.pay.total_amount,
		    is->ip);
	fail (is);
	return;
      }

      /* get max_fee */
      if (GNUNET_OK !=
	  TALER_string_to_amount (cmd->details.pay.max_fee,
				  &max_fee))
      {
	GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		    "Failed to parse max_fee `%s' at %u\n",
		    cmd->details.pay.max_fee,
		    is->ip);
	fail (is);
	return;
      }
      
      /* parse wire details */
      wire = json_loads (cmd->details.pay.wire_details,
                         JSON_REJECT_DUPLICATES,
                         NULL);
      if (NULL == wire)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    "Failed to parse wire details `%s' at %u\n",
                    cmd->details.pay.wire_details,
                    is->ip);
        fail (is);
        return;
      }
      TALER_hash_json (wire,
		       &h_wire);
      json_decref (wire);

      /* parse contract */
      contract = json_loads (cmd->details.pay.contract,
			     JSON_REJECT_DUPLICATES,
			     NULL);
      if (NULL == contract)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    "Failed to parse contract details `%s' at instruction %u\n",
                    cmd->details.pay.contract,
                    is->ip);
        fail (is);
        return;
      }
      TALER_hash_json (contract,
		       &h_contract);
      json_decref (contract);

      /* initialize 'pc' (FIXME: to do in a loop later...) */
      {
	const struct Command *ref;

	memset (&pc, 0, sizeof (pc));
	ref = find_command (is,
			    cmd->details.pay.coin_ref);
	GNUNET_assert (NULL != ref);
	switch (ref->oc)
	{
	case OC_WITHDRAW_SIGN:
	  pc.coin_priv = ref->details.reserve_withdraw.coin_priv;
	  pc.denom_pub = ref->details.reserve_withdraw.pk->key;
	  pc.denom_sig = ref->details.reserve_withdraw.sig;
	  break;
	default:
	  GNUNET_assert (0);
	}

	if (GNUNET_OK !=
	    TALER_string_to_amount (cmd->details.pay.amount_without_fee,
				    &pc.amount_without_fee))
	{
	  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		      "Failed to parse amount `%s' at %u\n",
		      cmd->details.pay.amount_without_fee,
		      is->ip);
	  fail (is);
	  return;
	}

	if (GNUNET_OK !=
	    TALER_string_to_amount (cmd->details.pay.amount_with_fee,
				    &pc.amount_with_fee))
	{
	  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
		      "Failed to parse amount `%s' at %u\n",
		      cmd->details.pay.amount_with_fee,
		      is->ip);
	  fail (is);
	  return;
	}	
      }
      
      if (0 == cmd->details.pay.refund_deadline.rel_value_us)
	refund_deadline = GNUNET_TIME_UNIT_ZERO_ABS; /* no refunds */
      else
	refund_deadline = GNUNET_TIME_relative_to_absolute (cmd->details.pay.refund_deadline);
      TALER_round_abs_time (&refund_deadline);
      timestamp = GNUNET_TIME_absolute_get ();
      TALER_round_abs_time (&timestamp);
      cmd->details.pay.ph 
	= TALER_MERCHANT_pay_wallet (merchant,
				     MERCHANT_URI "pay",
				     EXCHANGE_URI,
				     &h_wire,
				     &h_contract,
				     timestamp,
				     cmd->details.pay.transaction_id,
				     &merchant_pub,
				     refund_deadline,
				     1 /* num_coins */,
				     &pc /* coins */,
				     &max_fee,
				     &amount,
				     &pay_cb,
				     is);
    }
    if (NULL == cmd->details.pay.ph)
    {
      GNUNET_break (0);
      fail (is);
      return;
    }
    trigger_context_task ();
    return;
  default:
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unknown instruction %d at %u (%s)\n",
                cmd->oc,
                is->ip,
                cmd->label);
    fail (is);
    return;
  }
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Function run when the test terminates (good or bad).
 * Cleans up our state.
 *
 * @param cls the interpreter state.
 * @param tc unused
 */
static void
do_shutdown (void *cls,
             const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct InterpreterState *is = cls;
  struct Command *cmd;
  unsigned int i;
  
  shutdown_task = NULL;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Shutdown executing\n");
  for (i=0;OC_END != (cmd = &is->commands[i])->oc;i++)
  {
    switch (cmd->oc)
    {
    case OC_END:
      GNUNET_assert (0);
      break;
    case OC_ADMIN_ADD_INCOMING:
      if (NULL != cmd->details.admin_add_incoming.aih)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Command %u (%s) did not complete\n",
                    i,
                    cmd->label);
        TALER_EXCHANGE_admin_add_incoming_cancel (cmd->details.admin_add_incoming.aih);
        cmd->details.admin_add_incoming.aih = NULL;
      }
      break;
    case OC_WITHDRAW_STATUS:
      if (NULL != cmd->details.reserve_status.wsh)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Command %u (%s) did not complete\n",
                    i,
                    cmd->label);
        TALER_EXCHANGE_reserve_status_cancel (cmd->details.reserve_status.wsh);
        cmd->details.reserve_status.wsh = NULL;
      }
      break;
    case OC_WITHDRAW_SIGN:
      if (NULL != cmd->details.reserve_withdraw.wsh)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Command %u (%s) did not complete\n",
                    i,
                    cmd->label);
        TALER_EXCHANGE_reserve_withdraw_cancel (cmd->details.reserve_withdraw.wsh);
        cmd->details.reserve_withdraw.wsh = NULL;
      }
      if (NULL != cmd->details.reserve_withdraw.sig.rsa_signature)
      {
        GNUNET_CRYPTO_rsa_signature_free (cmd->details.reserve_withdraw.sig.rsa_signature);
        cmd->details.reserve_withdraw.sig.rsa_signature = NULL;
      }
      if (NULL != cmd->details.reserve_withdraw.blinding_key.rsa_blinding_key)
      {
        GNUNET_CRYPTO_rsa_blinding_key_free (cmd->details.reserve_withdraw.blinding_key.rsa_blinding_key);
        cmd->details.reserve_withdraw.blinding_key.rsa_blinding_key = NULL;
      }
      break;
    case OC_PAY:
      if (NULL != cmd->details.pay.ph)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Command %u (%s) did not complete\n",
                    i,
                    cmd->label);
        TALER_MERCHANT_pay_cancel (cmd->details.pay.ph);
        cmd->details.pay.ph = NULL;
      }
      break;
    default:
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Unknown instruction %d at %u (%s)\n",
                  cmd->oc,
                  i,
                  cmd->label);
      break;
    }
  }
  if (NULL != is->task)
  {
    GNUNET_SCHEDULER_cancel (is->task);
    is->task = NULL;
  }
  GNUNET_free (is);
  if (NULL != ctx_task)
  {
    GNUNET_SCHEDULER_cancel (ctx_task);
    ctx_task = NULL;
  }
  if (NULL != exchange)
  {
    TALER_EXCHANGE_disconnect (exchange);
    exchange = NULL;
  }
  if (NULL != merchant)
  {
    TALER_MERCHANT_fini (merchant);
    merchant = NULL;
  }
  if (NULL != ctx)
  {
    TALER_EXCHANGE_fini (ctx);
    ctx = NULL;
  }
}


/**
 * Functions of this type are called to provide the retrieved signing and
 * denomination keys of the exchange.  No TALER_EXCHANGE_*() functions should be called
 * in this callback.
 *
 * @param cls closure
 * @param keys information about keys of the exchange
 */
static void
cert_cb (void *cls,
         const struct TALER_EXCHANGE_Keys *keys)
{
  struct InterpreterState *is = cls;

  /* check that keys is OK */
#define ERR(cond) do { if(!(cond)) break; GNUNET_break (0); GNUNET_SCHEDULER_shutdown(); return; } while (0)
  ERR (NULL == keys);
  ERR (0 == keys->num_sign_keys);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Read %u signing keys\n",
              keys->num_sign_keys);
  ERR (0 == keys->num_denom_keys);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Read %u denomination keys\n",
              keys->num_denom_keys);
#undef ERR

  /* run actual tests via interpreter-loop */
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Certificate callback invoked, starting interpreter\n");
  is->keys = keys;
  is->task = GNUNET_SCHEDULER_add_now (&interpreter_run,
                                       is);
}


/**
 * Task that runs the context's event loop with the GNUnet scheduler.
 *
 * @param cls unused
 * @param tc scheduler context (unused)
 */
static void
context_task (void *cls,
              const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  long timeout;
  int max_fd;
  fd_set read_fd_set;
  fd_set write_fd_set;
  fd_set except_fd_set;
  struct GNUNET_NETWORK_FDSet *rs;
  struct GNUNET_NETWORK_FDSet *ws;
  struct GNUNET_TIME_Relative delay;

  ctx_task = NULL;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Event loop running\n");
  TALER_EXCHANGE_perform (ctx);
  TALER_MERCHANT_perform (merchant);
  max_fd = -1;
  timeout = -1;
  FD_ZERO (&read_fd_set);
  FD_ZERO (&write_fd_set);
  FD_ZERO (&except_fd_set);
  TALER_EXCHANGE_get_select_info (ctx,
                              &read_fd_set,
                              &write_fd_set,
                              &except_fd_set,
                              &max_fd,
                              &timeout);
  TALER_MERCHANT_get_select_info (merchant,
				  &read_fd_set,
				  &write_fd_set,
				  &except_fd_set,
				  &max_fd,
				  &timeout);
  if (timeout >= 0)
    delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
                                           timeout);
  else
    delay = GNUNET_TIME_UNIT_FOREVER_REL;
  rs = GNUNET_NETWORK_fdset_create ();
  GNUNET_NETWORK_fdset_copy_native (rs,
                                    &read_fd_set,
                                    max_fd + 1);
  ws = GNUNET_NETWORK_fdset_create ();
  GNUNET_NETWORK_fdset_copy_native (ws,
                                    &write_fd_set,
                                    max_fd + 1);
  ctx_task = GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT,
                                          delay,
                                          rs,
                                          ws,
                                          &context_task,
                                          cls);
  GNUNET_NETWORK_fdset_destroy (rs);
  GNUNET_NETWORK_fdset_destroy (ws);
}


/**
 * Main function that will be run by the scheduler.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param config configuration
 */
static void
run (void *cls,
     const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct InterpreterState *is;
  static struct Command commands[] =
  {
    /* Fill reserve with EUR:5.01, as withdraw fee is 1 ct per config */
    { .oc = OC_ADMIN_ADD_INCOMING,
      .label = "create-reserve-1",
      .expected_response_code = MHD_HTTP_OK,
      .details.admin_add_incoming.wire = "{ \"type\":\"TEST\", \"bank\":\"source bank\", \"account\":42 }",
      .details.admin_add_incoming.amount = "EUR:5.01" },
    /* Withdraw a 5 EUR coin, at fee of 1 ct */
    { .oc = OC_WITHDRAW_SIGN,
      .label = "withdraw-coin-1",
      .expected_response_code = MHD_HTTP_OK,
      .details.reserve_withdraw.reserve_reference = "create-reserve-1",
      .details.reserve_withdraw.amount = "EUR:5" },
    /* Check that deposit and withdraw operation are in history, and
       that the balance is now at zero */
    { .oc = OC_WITHDRAW_STATUS,
      .label = "withdraw-status-1",
      .expected_response_code = MHD_HTTP_OK,
      .details.reserve_status.reserve_reference = "create-reserve-1",
      .details.reserve_status.expected_balance = "EUR:0" },
    /* Try to pay with the 5 EUR coin (in full) */
    { .oc = OC_PAY,
      .label = "deposit-simple",
      .expected_response_code = MHD_HTTP_OK,
      .details.pay.total_amount = "EUR:5",
      .details.pay.max_fee = "EUR:0.5",
      .details.pay.coin_ref = "withdraw-coin-1",
      .details.pay.amount_with_fee = "EUR:5",
      .details.pay.amount_without_fee = "EUR:4.99",
      .details.pay.wire_details = "{ \"type\":\"TEST\", \"bank\":\"dest bank\", \"account\":42 }",
      .details.pay.contract = "{ \"items\":[ {\"name\":\"ice cream\", \"value\":1} ] }",
      .details.pay.transaction_id = 1 },

    /* Try to double-spend the 5 EUR coin with different wire details */
    { .oc = OC_PAY,
      .label = "deposit-double-1",
      .expected_response_code = MHD_HTTP_FORBIDDEN,
      .details.pay.total_amount = "EUR:5",
      .details.pay.max_fee = "EUR:0.5",
      .details.pay.coin_ref = "withdraw-coin-1",
      .details.pay.amount_with_fee = "EUR:5",
      .details.pay.amount_without_fee = "EUR:4.99",
      .details.pay.wire_details = "{ \"type\":\"TEST\", \"bank\":\"dest bank\", \"account\":43 }",
      .details.pay.contract = "{ \"items\":[{ \"name\":\"ice cream\", \"value\":1} ] }",
      .details.pay.transaction_id = 1 },
    /* Try to double-spend the 5 EUR coin at the same merchant (but different
       transaction ID) */
    { .oc = OC_PAY,
      .label = "deposit-double-2",
      .expected_response_code = MHD_HTTP_FORBIDDEN,
      .details.pay.total_amount = "EUR:5",
      .details.pay.max_fee = "EUR:0.5",
      .details.pay.coin_ref = "withdraw-coin-1",
      .details.pay.amount_with_fee = "EUR:5",
      .details.pay.amount_without_fee = "EUR:4.99",
      .details.pay.wire_details = "{ \"type\":\"TEST\", \"bank\":\"dest bank\", \"account\":42 }",
      .details.pay.contract = "{ \"items\":[ {\"name\":\"ice cream\", \"value\":1} ] }",
      .details.pay.transaction_id = 2 },
    /* Try to double-spend the 5 EUR coin at the same merchant (but different
       contract) */
    { .oc = OC_PAY,
      .label = "deposit-double-3",
      .expected_response_code = MHD_HTTP_FORBIDDEN,
      .details.pay.total_amount = "EUR:5",
      .details.pay.max_fee = "EUR:0.5",
      .details.pay.coin_ref = "withdraw-coin-1",
      .details.pay.amount_with_fee = "EUR:5",
      .details.pay.amount_without_fee = "EUR:4.99",
      .details.pay.wire_details = "{ \"type\":\"TEST\", \"bank\":\"dest bank\", \"account\":42 }",
      .details.pay.contract = "{ \"items\":[ {\"name\":\"ice cream\", \"value\":2} ] }",
      .details.pay.transaction_id = 1 },

    { .oc = OC_END }
  };

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
	      "Interpreter initializing\n");
  is = GNUNET_new (struct InterpreterState);
  is->commands = commands;

  ctx = TALER_EXCHANGE_init ();
  GNUNET_assert (NULL != ctx);
  merchant = TALER_MERCHANT_init ();
  GNUNET_assert (NULL != merchant);
  ctx_task = GNUNET_SCHEDULER_add_now (&context_task,
                                       ctx);
  exchange = TALER_EXCHANGE_connect (ctx,
                             EXCHANGE_URI,
                             &cert_cb, is,
                             TALER_EXCHANGE_OPTION_END);
  GNUNET_assert (NULL != exchange);
  shutdown_task
    = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply
                                    (GNUNET_TIME_UNIT_SECONDS, 150),
                                    &do_shutdown, is);
}


/**
 * Main function for the testcase for the exchange API.
 *
 * @param argc expected to be 1
 * @param argv expected to only contain the program name
 */
int
main (int argc,
      char * const *argv)
{
  /* Value from "gnunet-ecc -p test_merchant.priv" */
  const char *merchant_pub_str 
    = "5TRNSWAWHKBJ7G4T3PKRCQA6MCB3MX82F4M2XXS1653KE1V8RFPG";
  struct GNUNET_OS_Process *proc;
  struct GNUNET_OS_Process *exchanged;
  struct GNUNET_OS_Process *merchantd;
  
  GNUNET_log_setup ("test-merchant-api",
                    "WARNING",
                    NULL);
  GNUNET_assert (GNUNET_OK ==
		 GNUNET_STRINGS_string_to_data (merchant_pub_str,
						strlen (merchant_pub_str),
						&merchant_pub,
						sizeof (merchant_pub)));
  proc = GNUNET_OS_start_process (GNUNET_NO,
                                  GNUNET_OS_INHERIT_STD_ALL,
                                  NULL, NULL, NULL,
                                  "taler-exchange-keyup",
                                  "taler-exchange-keyup",
                                  "-d", "test-exchange-home",
                                  "-m", "test-exchange-home/master.priv",
                                  NULL);
  GNUNET_OS_process_wait (proc);
  GNUNET_OS_process_destroy (proc);
  exchanged = GNUNET_OS_start_process (GNUNET_NO,
                                   GNUNET_OS_INHERIT_STD_ALL,
                                   NULL, NULL, NULL,
                                   "taler-exchange-httpd",
                                   "taler-exchange-httpd",
                                   "-d", "test-exchange-home",
                                   NULL);
  /* give child time to start and bind against the socket */
  fprintf (stderr, "Waiting for taler-exchange-httpd to be ready");
  do
    {
      fprintf (stderr, ".");
      sleep (1);
    }
  while (0 != system ("wget -q -t 1 -T 1 " EXCHANGE_URI "keys -o /dev/null -O /dev/null"));
  fprintf (stderr, "\n");
  merchantd = GNUNET_OS_start_process (GNUNET_NO,
                                       GNUNET_OS_INHERIT_STD_ALL,
                                       NULL, NULL, NULL,
                                       "taler-merchant-httpd",
                                       "taler-merchant-httpd",
                                       "-c", "test_merchant.conf",
                                       NULL);
  /* give child time to start and bind against the socket */
  fprintf (stderr, "Waiting for taler-merchant-httpd to be ready");
  do
    {
      fprintf (stderr, ".");
      sleep (1);
    }
  while (0 != system ("wget -q -t 1 -T 1 " MERCHANT_URI " -o /dev/null -O /dev/null"));
  fprintf (stderr, "\n");
  result = GNUNET_SYSERR;
  GNUNET_SCHEDULER_run (&run, NULL);
  GNUNET_OS_process_kill (merchantd,
                          SIGTERM);
  GNUNET_OS_process_wait (merchantd);
  GNUNET_OS_process_destroy (merchantd);
  GNUNET_OS_process_kill (exchanged,
                          SIGTERM);
  GNUNET_OS_process_wait (exchanged);
  GNUNET_OS_process_destroy (exchanged);
  return (GNUNET_OK == result) ? 0 : 1;
}

/* end of test_merchant_api.c */