Trigger conflicting refunds

src/exchange-lib/exchange_api_refund.c

@@ -184,6 +184,10 @@ handle_refund_finished (void *cls,
     /* Client request was inconsistent; might be a currency missmatch
        problem.  */
     break;
+  case MHD_HTTP_CONFLICT:
+    /* Two refund requests were made about the same deposit, but
+       carrying different refund transaction ids.  */
+    break;
   case MHD_HTTP_INTERNAL_SERVER_ERROR:
     /* Server had an internal issue; we should retry, but this API
        leaves this to the application */

src/exchange-lib/test_exchange_api_new.c

@@ -500,6 +500,11 @@ run (void *cls,
       ("refund-ok-double", MHD_HTTP_OK,
        "EUR:5", "EUR:0.01", "deposit-refund-1"),
 
+    /* Previous /refund(s) had id == 0.  */
+    TALER_TESTING_cmd_refund_with_id
+      ("refund-conflicting", MHD_HTTP_CONFLICT,
+       "EUR:5", "EUR:0.01", "deposit-refund-1", 1),
+
     /**
      * Spend 4.99 EUR of the refunded 4.99 EUR coin (1ct gone
      * due to refund) (merchant would receive EUR:4.98 due to

src/exchange-lib/testing_api_cmd_refund.c

@@ -298,3 +298,42 @@ TALER_TESTING_cmd_refund (const char *label,
 
   return cmd;
 }
+
+/**
+ * Create a /refund test command, allows to specify refund
+ * transaction id.  Mainly used to create conflicting requests.
+ *
+ * @param label command label
+ * @param expected_response_code expected HTTP status code
+ * @param refund_amount the amount to ask a refund for
+ * @param refund_fee expected refund fee
+ * @param coin_reference reference to a command that can
+ *        provide a coin to be refunded.
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_refund_with_id
+  (const char *label,
+   unsigned int expected_response_code,
+   const char *refund_amount,
+   const char *refund_fee,
+   const char *coin_reference,
+   uint64_t refund_transaction_id)
+{
+  struct RefundState *rs;
+  struct TALER_TESTING_Command cmd;
+
+  rs = GNUNET_new (struct RefundState);
+
+  rs->expected_response_code = expected_response_code;
+  rs->refund_amount = refund_amount;
+  rs->refund_fee = refund_fee;
+  rs->coin_reference = coin_reference;
+  rs->refund_transaction_id = refund_transaction_id;
+
+  cmd.cls = rs;
+  cmd.label = label;
+  cmd.run = &refund_run;
+  cmd.cleanup = &refund_cleanup;
+
+  return cmd;
+}

src/include/taler_testing_lib.h

@@ -828,6 +828,26 @@ TALER_TESTING_cmd_check_bank_transfer_with_ref
 struct TALER_TESTING_Command
 TALER_TESTING_cmd_check_bank_empty (const char *label);
 
+/**
+ * Create a /refund test command, allows to specify refund
+ * transaction id.
+ *
+ * @param label command label
+ * @param expected_response_code expected HTTP status code
+ * @param refund_amount the amount to ask a refund for
+ * @param refund_fee expected refund fee
+ * @param coin_reference reference to a command that can
+ *        provide a coin to be refunded.
+ */
+struct TALER_TESTING_Command
+TALER_TESTING_cmd_refund_with_id
+  (const char *label,
+   unsigned int expected_response_code,
+   const char *refund_amount,
+   const char *refund_fee,
+   const char *deposit_reference,
+   uint64_t refund_transaction_id);
+
 /**
  * Create a /refund test command.
  *