circuit API

document how to test the TAN

1 files changed, 13 insertions, 1 deletions

diff --git a/libeufin/api-sandbox.rst b/libeufin/api-sandbox.rst
index 6afcac72..96ca0e0c 100644
--- a/libeufin/api-sandbox.rst
+++ b/libeufin/api-sandbox.rst
@@ -251,6 +251,17 @@ Cashouts
      Consult the `cashout rates call <cashout-rates_>`_ to learn
      about any applicable fee or exchange rate.
 
+   To test this operation without relying on any SMS/E-mail provider,
+   Libeufin offers two methods: defining an environment variable called
+   ``LIBEUFIN_CASHOUT_TEST_TAN`` or specifying the value ``file`` to
+   the ``tan_channel`` field of the `request object <cashout-request_>`_.
+   Assuming ``LIBEUFIN_CASHOUT_TEST_TAN`` is set to *T*, every */confirm*
+   operation can use *T* as the TAN.  Setting instead the ``tan_channel``
+   field to ``file`` will cause the server to (over)write every TAN to
+   ``/tmp/libeufin-cashout-tan.txt``.  If both are used, the environment
+   variable takes the precedence.
+
+
    **Request:**
 
    `CashoutRequest <cashout-request_>`_
@@ -259,7 +270,8 @@ Cashouts
 
      enum TanChannel {
        SMS = "sms",
-       EMAIL = "email"
+       EMAIL = "email",
+       FILE = "file"
      }
 
    .. _cashout-request: