Add configurable refund window

Add configuration model for enrollment refunds.

Use order info from otto in refund window calculation

Delete dupe tests. Extend tests to include window tests

Move ecom client from lib to djangoapps in openedx

openedx/core/djangoapps/commerce/__init__.py

@@ -0,0 +1 @@
+""" Thin Client for the Ecommerce API Service """

openedx/core/djangoapps/commerce/utils.py

@@ -0,0 +1,38 @@
+""" Commerce API Service. """
+from django.conf import settings
+from edx_rest_api_client.client import EdxRestApiClient
+from eventtracking import tracker
+
+ECOMMERCE_DATE_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
+
+
+def create_tracking_context(user):
+    """ Assembles attributes from user and request objects to be sent along
+    in ecommerce api calls for tracking purposes. """
+    context_tracker = tracker.get_tracker().resolve_context()
+
+    return {
+        'lms_user_id': user.id,
+        'lms_client_id': context_tracker.get('client_id'),
+        'lms_ip': context_tracker.get('ip'),
+    }
+
+
+def is_commerce_service_configured():
+    """
+    Return a Boolean indicating whether or not configuration is present to use
+    the external commerce service.
+    """
+    return bool(settings.ECOMMERCE_API_URL and settings.ECOMMERCE_API_SIGNING_KEY)
+
+
+def ecommerce_api_client(user):
+    """ Returns an E-Commerce API client setup with authentication for the specified user. """
+    return EdxRestApiClient(settings.ECOMMERCE_API_URL,
+                            settings.ECOMMERCE_API_SIGNING_KEY,
+                            user.username,
+                            user.profile.name,
+                            user.email,
+                            tracking_context=create_tracking_context(user),
+                            issuer=settings.JWT_ISSUER,
+                            expires_in=settings.JWT_EXPIRATION)