Implementing new style test instructions.

1 files changed, 1538 insertions, 0 deletions

diff --git a/src/lib/testing_api_cmd_pay.c b/src/lib/testing_api_cmd_pay.c
new file mode 100644
index 00000000..c7f3e878
--- /dev/null
+++ b/src/lib/testing_api_cmd_pay.c
@@ -0,0 +1,1538 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2018 Taler Systems SA
+
+  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, see
+  <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file lib/testing_api_cmd_pay.c
+ * @brief command to test the /pay feature.
+ * @author Marcello Stanisci
+ */
+
+#include "platform.h"
+#include <taler/taler_exchange_service.h>
+#include <taler/taler_testing_lib.h>
+#include <taler/taler_signatures.h>
+#include "taler_merchant_service.h"
+#include "taler_merchant_testing_lib.h"
+
+#define AMOUNT_WITH_FEE 0
+#define AMOUNT_WITHOUT_FEE 1
+#define REFUND_FEE 2
+
+struct PayState
+{
+  /**
+   * Contract terms hash code.
+   */
+  struct GNUNET_HashCode h_contract_terms;
+
+  /**
+   * The interpreter state.
+   */
+  struct TALER_TESTING_Interpreter *is;
+
+  /**
+   * Expected HTTP response status code.
+   */
+  unsigned int http_status;
+
+  /**
+   * Reference to a command that can provide a order id,
+   * typically a /proposal test command.
+   */
+  const char *proposal_reference;
+
+  /**
+   * Reference to a command that can provide a coin, so
+   * we can pay here.
+   */
+  const char *coin_reference;
+
+  /**
+   * The curl context; used to be fed to the merchant lib.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * The merchant base URL.
+   */
+  const char *merchant_url;
+
+  /**
+   * Amount to be paid, plus the deposit fee.
+   */
+  const char *amount_with_fee;
+
+  /**
+   * Amount to be paid, including NO fees.
+   */
+  const char *amount_without_fee;
+
+  /**
+   * Fee for refunding this payment.
+   */
+  const char *refund_fee;
+
+  /**
+   * Handle to the /pay operation.
+   */
+  struct TALER_MERCHANT_Pay *po;
+
+};
+
+
+struct CheckPaymentState
+{
+
+  /**
+   * Operation handle.
+   */
+  struct TALER_MERCHANT_CheckPaymentOperation *cpo;
+
+  /**
+   * The interpreter state.
+   */
+  struct TALER_TESTING_Interpreter *is;
+
+  /**
+   * Expected HTTP response status code.
+   */
+  unsigned int http_status;
+
+  /**
+   * Reference to a command that can provide a order id,
+   * typically a /proposal test command.
+   */
+  const char *proposal_reference;
+
+  /**
+   * GNUNET_YES if we expect the proposal was paid.
+   */
+  unsigned int expect_paid;
+
+  /**
+   * The curl context; used to be fed to the merchant lib.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * The merchant base URL.
+   */
+  const char *merchant_url;
+
+};
+
+
+struct PayAgainState
+{
+  
+  /**
+   * Expected HTTP response code.
+   */
+  unsigned int http_status;
+
+  /**
+   * Reference to the "pay" command to abort.
+   */
+  const char *pay_reference;
+
+  /**
+   * Reference to the coins to use.
+   */
+  const char *coin_reference;
+
+  /**
+   * Main CURL context.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * Merchant URL.
+   */
+  const char *merchant_url;
+
+  /**
+   * Refund fee.
+   */
+  const char *refund_fee;
+
+  /**
+   * Handle to a "pay again" operation.
+   */
+  struct TALER_MERCHANT_Pay *pao;
+
+  /**
+   * Interpreter state.
+   */
+  struct TALER_TESTING_Interpreter *is;
+};
+
+
+struct PayAbortState
+{
+  
+  /**
+   * Expected HTTP response code.
+   */
+  unsigned int http_status;
+
+  /**
+   * Reference to the "pay" command to abort.
+   */
+  const char *pay_reference;
+
+  /**
+   * Main CURL context.
+   */
+  struct GNUNET_CURL_Context *ctx;
+
+  /**
+   * Merchant URL.
+   */
+  const char *merchant_url;
+
+  /**
+   * Handle to a "pay abort" operation.
+   */
+  struct TALER_MERCHANT_Pay *pao;
+
+  /**
+   * Interpreter state.
+   */
+  struct TALER_TESTING_Interpreter *is;
+
+
+  /**
+   * FIXME.
+   */
+  unsigned int num_refunds;
+
+  /**
+   * FIXME.
+   */
+  struct TALER_MERCHANT_RefundEntry *res;
+
+  /**
+   * FIXME.
+   */
+  struct GNUNET_HashCode h_contract;
+
+  /**
+   * Merchant public key.
+   */
+  struct TALER_MerchantPublicKeyP merchant_pub;
+};
+
+
+struct PayAbortRefundState
+{
+  const char *abort_reference;
+
+  unsigned int num_coins;
+
+  const char *refund_amount;
+
+  const char *refund_fee;
+
+  struct TALER_TESTING_Interpreter *is;
+
+  /**
+   * Handle to the refund operation.
+   */
+  struct TALER_EXCHANGE_RefundHandle *rh;
+
+  /**
+   * Expected HTTP response code.
+   */
+  unsigned int http_status;
+
+  struct TALER_EXCHANGE_Handle *exchange;
+};
+
+
+
+/**
+ * Clean up after the command.  Run during forced termination
+ * (CTRL-C) or test failure or test success.
+ *
+ * @param cls closure
+ */
+static void
+check_payment_cleanup (void *cls,
+                       const struct TALER_TESTING_Command *cmd)
+{
+  struct CheckPaymentState *cps = cls;
+
+  if (NULL != cps->cpo)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Command `%s' was not terminated\n",
+                TALER_TESTING_interpreter_get_current_label (
+                  cps->is));
+    TALER_MERCHANT_check_payment_cancel (cps->cpo);  
+  }
+  GNUNET_free (cps);
+}
+
+
+/**
+ * Callback for GET /proposal issued at backend. Just check
+ * whether response code is as expected.
+ *
+ * @param cls closure
+ * @param http_status HTTP status code we got
+ * @param json full response we got
+ */
+static void
+check_payment_cb (void *cls,
+                  unsigned int http_status,
+                  const json_t *obj,
+                  int paid,
+                  int refunded,
+                  struct TALER_Amount *refund_amount,
+                  const char *payment_redirect_url)
+{
+  struct CheckPaymentState *cps = cls;
+
+  cps->cpo = NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "check payment: expected paid: %s: %d\n",
+              TALER_TESTING_interpreter_get_current_label (
+                cps->is),
+              cps->expect_paid);
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "check payment: paid: %d\n",
+              paid);
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "check payment: url: %s\n",
+              payment_redirect_url);
+
+  if (paid != cps->expect_paid)
+    TALER_TESTING_FAIL (cps->is);
+
+  if (cps->http_status != http_status)
+    TALER_TESTING_FAIL (cps->is);
+
+  TALER_TESTING_interpreter_next (cps->is);
+}
+
+/**
+ * Runs the command.  Note that upon return, the interpreter
+ * will not automatically run the next command, as the command
+ * may continue asynchronously in other scheduler tasks.  Thus,
+ * the command must ensure to eventually call
+ * #TALER_TESTING_interpreter_next() or
+ * #TALER_TESTING_interpreter_fail().
+ *
+ * @param is interpreter state
+ */
+static void
+check_payment_run (void *cls,
+                   const struct TALER_TESTING_Command *cmd,
+                   struct TALER_TESTING_Interpreter *is)
+{
+  struct CheckPaymentState *cps = cls;
+  const struct TALER_TESTING_Command *proposal_cmd;
+  const char *order_id;
+
+  cps->is = is;
+  proposal_cmd = TALER_TESTING_interpreter_lookup_command (
+    is, cps->proposal_reference);
+
+  if (NULL == proposal_cmd)
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_order_id (
+    proposal_cmd, 0, &order_id))
+    TALER_TESTING_FAIL (is);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Checking for order id `%s'\n",
+              order_id);
+
+  cps->cpo = TALER_MERCHANT_check_payment (
+    cps->ctx,
+    cps->merchant_url,
+    "default", // only default instance for now.
+    order_id,
+    NULL,
+    NULL,
+    NULL,
+    check_payment_cb,
+    cps);
+
+  GNUNET_assert (NULL != cps->cpo); 
+}
+
+/**
+ * Make a "check payment" test command.
+ *
+ * @param label command label.
+ * @param merchant_url merchant base url
+ * @param ctx CURL context.
+ * @param http_status expected HTTP response code.
+ * @param proposal_reference the proposal whose payment status
+ *        is going to be checked.
+ * @param expect_paid GNUNET_YES if we expect the proposal to be
+ *        paid, GNUNET_NO otherwise.
+ *
+ * @return the command
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_check_payment (
+  const char *label,
+  const char *merchant_url,
+  struct GNUNET_CURL_Context *ctx,
+  unsigned int http_status,
+  const char *proposal_reference,
+  unsigned int expect_paid)
+{
+  struct CheckPaymentState *cps;
+  struct TALER_TESTING_Command cmd;
+
+  cps = GNUNET_new (struct CheckPaymentState);
+  cps->http_status = http_status;
+  cps->proposal_reference = proposal_reference;
+  cps->expect_paid = expect_paid;
+  cps->ctx = ctx;
+  cps->merchant_url = merchant_url;
+
+  cmd.cls = cps;
+  cmd.label = label;
+  cmd.run = &check_payment_run;
+  cmd.cleanup = &check_payment_cleanup;
+
+  return cmd;
+
+}
+
+/**
+ * Parse the @a coins specification and grow the @a pc
+ * array with the coins found, updating @a npc.
+ *
+ * @param[in,out] pc pointer to array of coins found
+ * @param[in,out] npc length of array at @a pc
+ * @param[in] coins string specifying coins to add to @a pc,
+ *            clobbered in the process
+ * @param is interpreter state
+ * @param amount_with_fee
+ * @param amount_without_fee
+ * @param refund_fee
+ * @return #GNUNET_OK on success
+ */
+static int
+build_coins (struct TALER_MERCHANT_PayCoin **pc,
+             unsigned int *npc,
+             char *coins,
+             struct TALER_TESTING_Interpreter *is,
+             const char *amount_with_fee,
+             const char *amount_without_fee,
+             const char *refund_fee)
+{
+  char *token;
+
+  for (token = strtok (coins, ";");
+       NULL != token;
+       token = strtok (NULL, ";"))
+  {
+    const struct TALER_TESTING_Command *coin_cmd;
+    char *ctok;
+    unsigned int ci;
+    struct TALER_MERCHANT_PayCoin *icoin;
+
+    /* Token syntax is "LABEL[/NUMBER]" */
+    ctok = strchr (token, '/');
+    ci = 0;
+    if (NULL != ctok)
+    {
+      *ctok = '\0';
+      ctok++;
+      if (1 != sscanf (ctok,
+		       "%u",
+		       &ci))
+      {
+	GNUNET_break (0);
+	return GNUNET_SYSERR;
+      }
+    }
+
+    coin_cmd = TALER_TESTING_interpreter_lookup_command
+      (is, token);
+
+    if (NULL == coin_cmd)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+
+    GNUNET_array_grow (*pc,
+		       *npc,
+		       (*npc) + 1);
+
+    icoin = &(*pc)[(*npc)-1];
+
+    struct TALER_CoinSpendPrivateKeyP *coin_priv; 
+    const struct TALER_EXCHANGE_DenomPublicKey *denom_pub;
+    struct TALER_DenominationSignature *denom_sig;
+    struct TALER_Amount *denom_value;
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_TESTING_get_trait_coin_priv
+        (coin_cmd, 0, &coin_priv));
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_TESTING_get_trait_denom_pub
+        (coin_cmd, 0, &denom_pub));
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_TESTING_get_trait_denom_sig
+        (coin_cmd, 0, &denom_sig));
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_TESTING_get_trait_amount_obj
+        (coin_cmd, 0, &denom_value));
+
+    icoin->coin_priv = *coin_priv;
+    icoin->denom_pub = denom_pub->key;
+    icoin->denom_sig = *denom_sig;
+    icoin->denom_value = *denom_value;
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_TESTING_get_trait_url
+        (coin_cmd, 0, &icoin->exchange_url)); 
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_string_to_amount
+        (amount_with_fee, &icoin->amount_with_fee));
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_string_to_amount
+        (amount_without_fee, &icoin->amount_without_fee));
+
+    GNUNET_assert
+      (GNUNET_OK == TALER_string_to_amount
+        (refund_fee, &icoin->refund_fee));
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * 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 ec taler-specific error object
+ * @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,
+        enum TALER_ErrorCode ec,
+        const json_t *obj)
+{
+  struct PayState *ps = cls;
+
+  struct GNUNET_CRYPTO_EddsaSignature sig;
+  const char *error_name;
+  unsigned int error_line;
+  const struct GNUNET_CRYPTO_EddsaPublicKey *merchant_pub;
+  const struct TALER_TESTING_Command *proposal_cmd;
+
+  ps->po = NULL;
+  if (ps->http_status != http_status)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u (%d) to command %s\n",
+                http_status,
+                ec,
+                TALER_TESTING_interpreter_get_current_label (
+                  ps->is));
+    TALER_TESTING_FAIL (ps->is);
+  }
+  if (MHD_HTTP_OK == http_status)
+  {
+    /* Check signature */
+    struct PaymentResponsePS mr;
+    struct GNUNET_JSON_Specification spec[] = {
+      GNUNET_JSON_spec_fixed_auto ("sig",
+                                   &sig),
+      GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
+				   &ps->h_contract_terms),
+      GNUNET_JSON_spec_end ()
+    };
+
+    GNUNET_assert (GNUNET_OK == GNUNET_JSON_parse (
+      obj, spec,
+      &error_name,
+      &error_line));
+
+    mr.purpose.purpose = htonl (
+      TALER_SIGNATURE_MERCHANT_PAYMENT_OK);
+    mr.purpose.size = htonl (sizeof (mr));
+    mr.h_contract_terms = ps->h_contract_terms;
+
+    /* proposal reference was used at least once, at this point */
+    GNUNET_assert
+      ( NULL !=
+      ( proposal_cmd = TALER_TESTING_interpreter_lookup_command
+      (ps->is, ps->proposal_reference)));
+
+    if (GNUNET_OK != TALER_TESTING_get_trait_peer_key_pub
+        (proposal_cmd, 0, &merchant_pub))
+      TALER_TESTING_FAIL (ps->is);
+
+    if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (
+      TALER_SIGNATURE_MERCHANT_PAYMENT_OK,
+      &mr.purpose, &sig,
+      merchant_pub))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Merchant signature given in response to /pay"
+                  " invalid\n");
+      TALER_TESTING_FAIL (ps->is);
+    }
+  }
+
+  TALER_TESTING_interpreter_next (ps->is);
+}
+
+/**
+ * FIXME
+ */
+static void
+pay_abort_cb (void *cls,
+              unsigned int http_status,
+              enum TALER_ErrorCode ec,
+              const struct TALER_MerchantPublicKeyP *merchant_pub,
+              const struct GNUNET_HashCode *h_contract,
+              unsigned int num_refunds,
+              const struct TALER_MERCHANT_RefundEntry *res,
+              const json_t *obj)
+{
+  struct PayAbortState *pas = cls;
+
+  pas->pao = NULL;
+  if (pas->http_status != http_status)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u (%d) to command %s\n",
+                http_status,
+                ec,
+                TALER_TESTING_interpreter_get_current_label
+                  (pas->is));
+    TALER_TESTING_FAIL (pas->is);
+  }
+  if ( (MHD_HTTP_OK == http_status) &&
+       (TALER_EC_NONE == ec) )
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Received %u refunds\n",
+                num_refunds);
+    pas->num_refunds = num_refunds;
+
+    pas->res = GNUNET_new_array
+      (num_refunds, struct TALER_MERCHANT_RefundEntry);
+
+    memcpy (pas->res, res,
+	    num_refunds * sizeof
+              (struct TALER_MERCHANT_RefundEntry));
+    pas->h_contract = *h_contract;
+    pas->merchant_pub = *merchant_pub;
+  }
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Successful pay-abort (HTTP status: %u)\n",
+              http_status);
+  TALER_TESTING_interpreter_next (pas->is);
+}
+
+
+/**
+ * @param cls the closure.  Will be a "pay" or "pay-abort" state,
+ *        depending on whether the caller was "pay" or "pay abort"
+ *        run method.
+ *
+ * @return handle to the operation, NULL if errors occur.
+ */
+static struct TALER_MERCHANT_Pay *
+_pay_run (const char *merchant_url,
+          struct GNUNET_CURL_Context *ctx,
+          const char *coin_reference,
+          const char *proposal_reference,
+          struct TALER_TESTING_Interpreter *is,
+          const char *amount_with_fee,
+          const char *amount_without_fee,
+          const char *refund_fee,
+          struct TALER_MERCHANT_Pay * (*api_func) (),
+          void (*api_cb) (),
+          void *cls)
+{
+  const struct TALER_TESTING_Command *proposal_cmd;
+  const char *contract_terms;
+  json_t *ct;
+  const char *order_id;
+  struct GNUNET_TIME_Absolute refund_deadline;
+  struct GNUNET_TIME_Absolute pay_deadline;
+  struct GNUNET_TIME_Absolute timestamp;
+  struct TALER_MerchantPublicKeyP merchant_pub;
+  struct GNUNET_HashCode h_wire;
+  const struct GNUNET_HashCode *h_proposal;
+  struct TALER_Amount total_amount;
+  struct TALER_Amount max_fee;
+  const char *error_name;
+  unsigned int error_line;
+  struct TALER_MERCHANT_PayCoin *pay_coins;
+  unsigned int npay_coins;
+  char *cr;
+  struct TALER_MerchantSignatureP *merchant_sig;
+  struct TALER_MERCHANT_Pay *ret;
+
+  proposal_cmd = TALER_TESTING_interpreter_lookup_command
+    (is, proposal_reference);
+
+  if (NULL == proposal_cmd)
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_contract_terms
+    (proposal_cmd, 0, &contract_terms))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  json_error_t error;
+  if (NULL ==
+     (ct = json_loads (contract_terms,
+                       JSON_COMPACT,
+                       &error)))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  /* Get information that needs to be put verbatim in the
+   * deposit permission */
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_string ("order_id",
+                             &order_id),
+    GNUNET_JSON_spec_absolute_time ("refund_deadline",
+                                    &refund_deadline),
+    GNUNET_JSON_spec_absolute_time ("pay_deadline",
+                                    &pay_deadline),
+    GNUNET_JSON_spec_absolute_time ("timestamp",
+                                    &timestamp),
+    GNUNET_JSON_spec_fixed_auto ("merchant_pub",
+                                 &merchant_pub),
+    GNUNET_JSON_spec_fixed_auto ("H_wire",
+                                 &h_wire),
+    TALER_JSON_spec_amount ("amount",
+                            &total_amount),
+    TALER_JSON_spec_amount ("max_fee",
+                            &max_fee),
+    GNUNET_JSON_spec_end()
+  };
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (ct,
+                         spec,
+                         &error_name,
+                         &error_line))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Parser failed on %s:%u\n",
+                error_name,
+                error_line);
+    fprintf (stderr, "%s\n", contract_terms);
+    GNUNET_break_op (0);
+    return NULL;
+  }
+
+  cr = GNUNET_strdup (coin_reference);
+  pay_coins = NULL;
+  npay_coins = 0;
+  if (GNUNET_OK !=
+      build_coins (&pay_coins,
+                   &npay_coins,
+	           cr,
+                   is,
+                   amount_with_fee,
+                   amount_without_fee,
+                   refund_fee))
+  {
+    GNUNET_array_grow (pay_coins,
+                       npay_coins,
+		       0);
+    GNUNET_free (cr);
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  GNUNET_free (cr);
+  if (GNUNET_OK != TALER_TESTING_get_trait_merchant_sig
+    (proposal_cmd, 0, &merchant_sig))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_h_contract_terms
+    (proposal_cmd, 0, &h_proposal))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  ret = api_func (ctx,
+                  merchant_url,
+                  "default", // instance
+                  h_proposal,
+                  &total_amount,
+                  &max_fee,
+                  &merchant_pub,
+                  merchant_sig,
+                  timestamp,
+                  refund_deadline,
+                  pay_deadline,
+                  &h_wire,
+                  order_id,
+                  npay_coins,
+                  pay_coins,
+                  api_cb,
+                  cls);
+
+  GNUNET_array_grow (pay_coins,
+                     npay_coins,
+                     0);
+  return ret;
+}
+
+/**
+ * Runs the command.  Note that upon return, the interpreter
+ * will not automatically run the next command, as the command
+ * may continue asynchronously in other scheduler tasks.  Thus,
+ * the command must ensure to eventually call
+ * #TALER_TESTING_interpreter_next() or
+ * #TALER_TESTING_interpreter_fail().
+ *
+ * @param is interpreter state
+ */
+static void
+pay_run (void *cls,
+         const struct TALER_TESTING_Command *cmd,
+         struct TALER_TESTING_Interpreter *is)
+{
+
+  struct PayState *ps = cls;
+  
+  ps->is = is;
+  if ( NULL == 
+     ( ps->po = _pay_run (ps->merchant_url,
+                          ps->ctx,
+                          ps->coin_reference,
+                          ps->proposal_reference,
+                          is,
+                          ps->amount_with_fee,
+                          ps->amount_without_fee,
+                          ps->refund_fee,
+                          &TALER_MERCHANT_pay_wallet,
+                          &pay_cb,
+                          ps)) )
+    TALER_TESTING_FAIL (is);
+}
+
+/**
+ * Clean up after the command.  Run during forced termination
+ * (CTRL-C) or test failure or test success.
+ *
+ * @param cls closure
+ */
+static void
+pay_cleanup (void *cls,
+             const struct TALER_TESTING_Command *cmd)
+{
+  struct PayState *ps = cls;
+
+  if (NULL != ps->po)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Command `%s' did not complete.\n",
+                TALER_TESTING_interpreter_get_current_label (
+                  ps->is));
+    TALER_MERCHANT_pay_cancel (ps->po);
+  }
+
+  GNUNET_free (ps);
+}
+
+
+/**
+ * Extract information from a command that is useful for other
+ * commands.
+ *
+ * @param cls closure
+ * @param ret[out] result (could be anything)
+ * @param trait name of the trait
+ * @param selector more detailed information about which object
+ *                 to return in case there were multiple generated
+ *                 by the command
+ * @return #GNUNET_OK on success
+ */
+static int
+pay_traits (void *cls,
+            void **ret,
+            const char *trait,
+            unsigned int index)
+{
+
+  struct PayState *ps = cls;
+  const char *order_id;
+  const struct TALER_TESTING_Command *proposal_cmd;
+  struct GNUNET_CRYPTO_EddsaPublicKey *merchant_pub;
+
+  if ( NULL ==
+     ( proposal_cmd = TALER_TESTING_interpreter_lookup_command
+       (ps->is, ps->proposal_reference)))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_order_id
+      (proposal_cmd, 0, &order_id))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_peer_key_pub
+      (proposal_cmd,
+       0,
+       (const struct GNUNET_CRYPTO_EddsaPublicKey **)
+         &merchant_pub))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+
+  struct TALER_TESTING_Trait traits[] = {
+    TALER_TESTING_make_trait_amount
+      (AMOUNT_WITH_FEE, ps->amount_with_fee),
+    TALER_TESTING_make_trait_amount
+      (AMOUNT_WITHOUT_FEE, ps->amount_without_fee),
+    TALER_TESTING_make_trait_amount
+      (REFUND_FEE, ps->refund_fee),
+    TALER_TESTING_make_trait_proposal_reference
+      (0, ps->proposal_reference),
+    TALER_TESTING_make_trait_coin_reference
+      (0, ps->coin_reference),
+    TALER_TESTING_make_trait_order_id (0, order_id),
+    TALER_TESTING_make_trait_peer_key_pub (0, merchant_pub),
+    TALER_TESTING_trait_end ()
+  };
+
+  return TALER_TESTING_get_trait (traits,
+                                  ret,
+                                  trait,
+                                  index);
+
+  return GNUNET_SYSERR;
+}
+
+/**
+ * Make a "pay" test command.
+ *
+ * @param label command label.
+ * @param merchant_url merchant base url
+ * @param ctx CURL context.
+ * @param http_status expected HTTP response code.
+ * @param proposal_reference the proposal whose payment status
+ *        is going to be checked.
+ * @param coin_reference reference to any command which is able
+ *        to provide coins to use for paying.
+ * @param amount_with_fee amount to pay, including the deposit
+ *        fee
+ * @param amount_without_fee amount to pay, no fees included.
+ * @param refund_fee fee for refunding this payment.
+ *
+ * @return the command
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_pay (
+  const char *label,
+  const char *merchant_url,
+  struct GNUNET_CURL_Context *ctx,
+  unsigned int http_status,
+  const char *proposal_reference,
+  const char *coin_reference,
+  const char *amount_with_fee,
+  const char *amount_without_fee,
+  const char *refund_fee)
+{
+  struct PayState *ps;
+  struct TALER_TESTING_Command cmd;
+
+  ps = GNUNET_new (struct PayState);
+  ps->http_status = http_status;
+  ps->proposal_reference = proposal_reference;
+  ps->coin_reference = coin_reference;
+  ps->ctx = ctx;
+  ps->merchant_url = merchant_url;
+  ps->amount_with_fee = amount_with_fee;
+  ps->amount_without_fee = amount_without_fee;
+  ps->refund_fee = refund_fee;
+
+  cmd.cls = ps;
+  cmd.label = label;
+  cmd.run = &pay_run;
+  cmd.cleanup = &pay_cleanup;
+  cmd.traits = &pay_traits;
+
+  return cmd;
+
+}
+
+
+/**
+ * Clean up after the command.  Run during forced termination
+ * (CTRL-C) or test failure or test success.
+ *
+ * @param cls closure
+ */
+static void
+pay_abort_cleanup (void *cls,
+                   const struct TALER_TESTING_Command *cmd)
+{
+  struct PayAbortState *pas = cls;
+
+  if (NULL != pas->pao)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Command `%s' did not complete.\n",
+                TALER_TESTING_interpreter_get_current_label (
+                  pas->is));
+    TALER_MERCHANT_pay_cancel (pas->pao);
+  }
+
+  GNUNET_free (pas);
+}
+
+/**
+ * Runs the command.  Note that upon return, the interpreter
+ * will not automatically run the next command, as the command
+ * may continue asynchronously in other scheduler tasks.  Thus,
+ * the command must ensure to eventually call
+ * #TALER_TESTING_interpreter_next() or
+ * #TALER_TESTING_interpreter_fail().
+ *
+ * @param is interpreter state
+ */
+static void
+pay_abort_run (void *cls,
+               const struct TALER_TESTING_Command *cmd,
+               struct TALER_TESTING_Interpreter *is)
+{
+  
+  struct PayAbortState *pas = cls;
+  const struct TALER_TESTING_Command *pay_cmd;
+
+  const char *proposal_reference;
+  const char *coin_reference;
+  const char *amount_with_fee;
+  const char *amount_without_fee;
+  const char *refund_fee;
+  
+  pas->is = is;
+  pay_cmd = TALER_TESTING_interpreter_lookup_command
+    (is, pas->pay_reference);
+  if (NULL == pay_cmd)
+    TALER_TESTING_FAIL (is);
+  
+  if (GNUNET_OK != TALER_TESTING_get_trait_proposal_reference
+      (pay_cmd, 0, &proposal_reference))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_coin_reference
+      (pay_cmd, 0, &coin_reference))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_amount
+    (pay_cmd, AMOUNT_WITH_FEE, &amount_with_fee))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_amount
+    (pay_cmd, AMOUNT_WITHOUT_FEE, &amount_without_fee))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_amount
+    (pay_cmd, REFUND_FEE, &refund_fee))
+    TALER_TESTING_FAIL (is);
+
+  if ( NULL ==
+     ( pas->pao = _pay_run (pas->merchant_url,
+                            pas->ctx,
+                            coin_reference,
+                            proposal_reference,
+                            is,
+                            amount_with_fee,
+                            amount_without_fee,
+                            refund_fee,
+                            &TALER_MERCHANT_pay_abort,
+                            &pay_abort_cb,
+                            pas)) )
+    TALER_TESTING_FAIL (is);
+}
+
+/**
+ * Extract information from a command that is useful for other
+ * commands.
+ *
+ * @param cls closure
+ * @param ret[out] result (could be anything)
+ * @param trait name of the trait
+ * @param selector more detailed information about which object
+ *                 to return in case there were multiple generated
+ *                 by the command
+ * @return #GNUNET_OK on success
+ */
+static int
+pay_abort_traits (void *cls,
+                  void **ret,
+                  const char *trait,
+                  unsigned int index)
+{
+  struct PayAbortState *pas = cls;
+
+  struct TALER_TESTING_Trait traits[] = {
+    TALER_TESTING_make_trait_peer_key_pub
+      (0, &pas->merchant_pub.eddsa_pub),
+    TALER_TESTING_make_trait_h_contract_terms
+      (0, &pas->h_contract),
+    TALER_TESTING_make_trait_refund_entry
+      (0, pas->res),
+    TALER_TESTING_make_trait_uint (0, &pas->num_refunds),
+    TALER_TESTING_trait_end ()
+  };
+
+  return TALER_TESTING_get_trait (traits,
+                                  ret,
+                                  trait,
+                                  index);
+
+  return GNUNET_SYSERR;
+}
+
+/**
+ * Make a "pay abort" test command.
+ *
+ * @param label command label
+ * @param merchant_url merchant base URL
+ * @param pay_reference reference to the payment to abort
+ * @param ctx main CURL context
+ * @param http_status expected HTTP response code
+ *
+ * @return the command
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_pay_abort (const char *label,
+                             const char *merchant_url,
+                             const char *pay_reference,
+                             struct GNUNET_CURL_Context *ctx,
+                             unsigned int http_status)
+{
+  struct PayAbortState *pas;
+  struct TALER_TESTING_Command cmd;
+
+  pas = GNUNET_new (struct PayAbortState);
+  pas->http_status = http_status;
+  pas->pay_reference = pay_reference;
+  pas->ctx = ctx;
+  pas->merchant_url = merchant_url;
+
+  cmd.cls = pas;
+  cmd.label = label;
+  cmd.run = &pay_abort_run;
+  cmd.cleanup = &pay_abort_cleanup;
+  cmd.traits = &pay_abort_traits;
+  
+  return cmd;
+}
+
+/**
+ * Function called with the result of a /pay again 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 ec taler-specific error object
+ * @param obj the received JSON reply, should be kept as proof
+ *        (and, in case of errors, be forwarded to the customer)
+ */
+static void
+pay_again_cb (void *cls,
+	      unsigned int http_status,
+	      enum TALER_ErrorCode ec,
+	      const json_t *obj)
+{
+  struct PayAgainState *pas = cls;
+  struct GNUNET_CRYPTO_EddsaSignature sig;
+  const char *error_name;
+  unsigned int error_line;
+  const struct TALER_TESTING_Command *pay_cmd;
+  const struct GNUNET_CRYPTO_EddsaPublicKey *merchant_pub;
+
+  pas->pao = NULL;
+  if (pas->http_status != http_status)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u (%d) to command %s\n",
+                http_status,
+                ec,
+                TALER_TESTING_interpreter_get_current_label
+                  (pas->is));
+    TALER_TESTING_interpreter_fail (pas->is);
+    return;
+  }
+
+  if ( NULL ==
+     ( pay_cmd = TALER_TESTING_interpreter_lookup_command
+       (pas->is, pas->pay_reference)))
+    TALER_TESTING_FAIL (pas->is);
+
+  if (MHD_HTTP_OK == http_status)
+  {
+    struct PaymentResponsePS mr;
+    /* Check signature */
+    struct GNUNET_JSON_Specification spec[] = {
+      GNUNET_JSON_spec_fixed_auto ("sig",
+				   &sig),
+      GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
+				   &mr.h_contract_terms),
+      GNUNET_JSON_spec_end ()
+    };
+
+    GNUNET_assert (GNUNET_OK == GNUNET_JSON_parse (obj,
+                                                   spec,
+                                                   &error_name,
+                                                   &error_line));
+    mr.purpose.purpose = htonl
+      (TALER_SIGNATURE_MERCHANT_PAYMENT_OK);
+    mr.purpose.size = htonl (sizeof (mr));
+
+    if (GNUNET_OK != TALER_TESTING_get_trait_peer_key_pub
+        (pay_cmd, 0, &merchant_pub))
+      TALER_TESTING_FAIL (pas->is);
+
+    if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify
+      (TALER_SIGNATURE_MERCHANT_PAYMENT_OK,
+       &mr.purpose,
+       &sig,
+       merchant_pub))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Merchant signature given in"
+                  " response to /pay invalid\n");
+      TALER_TESTING_FAIL (pas->is);
+    }
+  }
+
+  TALER_TESTING_interpreter_next (pas->is);
+}
+
+/**
+ * Runs the command.  Note that upon return, the interpreter
+ * will not automatically run the next command, as the command
+ * may continue asynchronously in other scheduler tasks.  Thus,
+ * the command must ensure to eventually call
+ * #TALER_TESTING_interpreter_next() or
+ * #TALER_TESTING_interpreter_fail().
+ *
+ * @param is interpreter state
+ */
+static void
+pay_again_run (void *cls,
+               const struct TALER_TESTING_Command *cmd,
+               struct TALER_TESTING_Interpreter *is)
+{
+  struct PayAgainState *pas = cls;
+  const struct TALER_TESTING_Command *pay_cmd;
+
+  const char *proposal_reference;
+  const char *amount_with_fee;
+  const char *amount_without_fee;
+  
+  pas->is = is;
+  pay_cmd = TALER_TESTING_interpreter_lookup_command
+    (is, pas->pay_reference);
+  if (NULL == pay_cmd)
+    TALER_TESTING_FAIL (is);
+  
+  if (GNUNET_OK != TALER_TESTING_get_trait_proposal_reference
+      (pay_cmd, 0, &proposal_reference))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_amount
+    (pay_cmd, AMOUNT_WITH_FEE, &amount_with_fee))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_amount
+    (pay_cmd, AMOUNT_WITHOUT_FEE, &amount_without_fee))
+    TALER_TESTING_FAIL (is);
+
+  if ( NULL ==
+     ( pas->pao = _pay_run (pas->merchant_url,
+                            pas->ctx,
+                            pas->coin_reference,
+                            proposal_reference,
+                            is,
+                            amount_with_fee,
+                            amount_without_fee,
+                            pas->refund_fee,
+                            &TALER_MERCHANT_pay_wallet,
+                            &pay_again_cb,
+                            pas)) )
+    TALER_TESTING_FAIL (is);
+}
+
+/**
+ * Clean up after the command.  Run during forced termination
+ * (CTRL-C) or test failure or test success.
+ *
+ * @param cls closure
+ */
+static void
+pay_again_cleanup (void *cls,
+                   const struct TALER_TESTING_Command *cmd)
+{
+  struct PayAgainState *pas = cls;
+
+  if (NULL != pas->pao)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Command `%s' did not complete.\n",
+                TALER_TESTING_interpreter_get_current_label (
+                  pas->is));
+    TALER_MERCHANT_pay_cancel (pas->pao);
+  }
+
+  GNUNET_free (pas);
+}
+
+/**
+ * Make a "pay again" test command.
+ *
+ * @param label command label
+ * @param merchant_url merchant base URL
+ * @param pay_reference reference to the payment to replay
+ * @param coin_reference reference to the coins to use
+ * @param ctx main CURL context
+ * @param http_status expected HTTP response code
+ *
+ * @return the command
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_pay_again (const char *label,
+                             const char *merchant_url,
+                             const char *pay_reference,
+                             const char *coin_reference,
+                             const char *refund_fee,
+                             struct GNUNET_CURL_Context *ctx,
+                             unsigned int http_status)
+{
+
+  struct PayAgainState *pas;
+  struct TALER_TESTING_Command cmd;
+
+  pas = GNUNET_new (struct PayAgainState);
+  pas->http_status = http_status;
+  pas->pay_reference = pay_reference;
+  pas->coin_reference = coin_reference;
+  pas->ctx = ctx;
+  pas->merchant_url = merchant_url;
+  pas->refund_fee = refund_fee;
+
+  cmd.cls = pas;
+  cmd.label = label;
+  cmd.run = &pay_again_run;
+  cmd.cleanup = &pay_again_cleanup;
+  
+  return cmd;
+}
+
+
+/**
+ * Callbacks of this type are used to serve the result of
+ * submitting a refund request to an exchange.
+ *
+ * @param cls closure
+ * @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 ec taler-specific error code, #TALER_EC_NONE on success
+ * @param sign_key exchange key used to sign @a obj, or NULL
+ * @param obj the received JSON reply, should be kept as proof
+ *        (and, in particular, be forwarded to the customer)
+ */
+static void
+abort_refund_cb (void *cls,
+		 unsigned int http_status,
+		 enum TALER_ErrorCode ec,
+		 const struct TALER_ExchangePublicKeyP *sign_key,
+		 const json_t *obj)
+{
+  struct PayAbortRefundState *pars = cls;
+
+  pars->rh = NULL;
+  if (pars->http_status != http_status)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u (%d) to command %s\n",
+                http_status,
+                ec,
+                TALER_TESTING_interpreter_get_current_label
+                  (pars->is));
+    TALER_TESTING_interpreter_fail (pars->is);
+    return;
+  }
+  TALER_TESTING_interpreter_next (pars->is);
+}
+
+/**
+ * FIXME.
+ */
+static void
+pay_abort_refund_cleanup (void *cls,
+                          const struct TALER_TESTING_Command *cmd)
+{
+  struct PayAbortRefundState *pars = cls;
+
+  if (NULL != pars->rh)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Command `%s' did not complete.\n",
+                TALER_TESTING_interpreter_get_current_label (
+                  pars->is));
+    TALER_EXCHANGE_refund_cancel (pars->rh);
+  }
+  GNUNET_free (pars);
+}
+
+/**
+ * FIXME.
+ */
+static void
+pay_abort_refund_run (void *cls,
+                      const struct TALER_TESTING_Command *cmd,
+                      struct TALER_TESTING_Interpreter *is)
+{
+  struct PayAbortRefundState *pars = cls;
+  struct TALER_Amount refund_fee;
+  struct TALER_Amount refund_amount;
+  const struct TALER_MERCHANT_RefundEntry *refund_entry;
+  unsigned int *num_refunds;
+  const struct TALER_TESTING_Command *abort_cmd;
+  const struct GNUNET_CRYPTO_EddsaPublicKey *merchant_pub;
+  const struct GNUNET_HashCode *h_contract_terms;
+
+  pars->is = is;
+
+  if ( NULL ==
+     ( abort_cmd = TALER_TESTING_interpreter_lookup_command
+       (is, pars->abort_reference)) )
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_uint
+      (abort_cmd, 0, &num_refunds))
+    TALER_TESTING_FAIL (is);
+
+  if (pars->num_coins >= *num_refunds)
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_h_contract_terms
+      (abort_cmd, 0, &h_contract_terms))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_peer_key_pub
+      (abort_cmd, 0, &merchant_pub))
+    TALER_TESTING_FAIL (is);
+
+  if (GNUNET_OK != TALER_TESTING_get_trait_refund_entry
+      (abort_cmd, 0, &refund_entry))
+    TALER_TESTING_FAIL (is);
+
+  GNUNET_assert (GNUNET_OK == TALER_string_to_amount 
+    (pars->refund_amount, &refund_amount));
+  GNUNET_assert (GNUNET_OK == TALER_string_to_amount 
+    (pars->refund_fee, &refund_fee));
+
+  pars->rh = TALER_EXCHANGE_refund2
+    (pars->exchange,
+     &refund_amount,
+     &refund_fee,
+     h_contract_terms,
+     &refund_entry->coin_pub,
+     refund_entry->rtransaction_id,
+     (const struct TALER_MerchantPublicKeyP *) merchant_pub,
+     &refund_entry->merchant_sig,
+     &abort_refund_cb,
+     pars);
+
+  GNUNET_assert (NULL != pars->rh);
+}
+
+
+/**
+ * FIXME.
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_pay_abort_refund
+  (const char *label,
+   struct TALER_EXCHANGE_Handle *exchange,
+   const char *abort_reference,
+   unsigned int num_coins,
+   const char *refund_amount,
+   const char *refund_fee,
+   unsigned int http_status)
+{
+  struct PayAbortRefundState *pars;
+  struct TALER_TESTING_Command cmd;
+
+  pars = GNUNET_new (struct PayAbortRefundState);
+  pars->abort_reference = abort_reference;
+  pars->num_coins = num_coins;
+  pars->refund_amount = refund_amount;
+  pars->refund_fee = refund_fee;
+  pars->http_status = http_status;
+  pars->exchange = exchange;
+
+  cmd.cls = pars;
+  cmd.label = label;
+  cmd.run = &pay_abort_refund_run;
+  cmd.cleanup = &pay_abort_refund_cleanup;
+
+  return cmd;
+}
+
+/* end of testing_api_cmd_pay.c */