From b93f0763a280c6e068a27e492764613d93480c4b Mon Sep 17 00:00:00 2001
From: Angela Tran <angela@compiler.la>
Date: Wed, 1 May 2024 23:13:22 +0000
Subject: [PATCH] refactor: show system enrollment error page if 500 during
 /token

---
 .../templates/enrollment/index.html           |  6 +++++
 benefits/enrollment/urls.py                   |  1 +
 benefits/enrollment/views.py                  | 18 +++++++++++--
 tests/pytest/enrollment/test_views.py         | 26 +++++++++++++++++++
 4 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/benefits/enrollment/templates/enrollment/index.html b/benefits/enrollment/templates/enrollment/index.html
index bc231a9f3..c48cf9129 100644
--- a/benefits/enrollment/templates/enrollment/index.html
+++ b/benefits/enrollment/templates/enrollment/index.html
@@ -41,6 +41,12 @@ <h1 class="pb-lg-8 pb-4">
       $.ajax({ dataType: "script", attrs: { nonce: "{{ request.csp_nonce }}"}, url: "{{ card_tokenize_url }}" })
           .done(function() {
           $.get("{{ access_token_url }}", function(data) {
+              if (data.redirect) {
+                // https://stackoverflow.com/a/42469170
+                // use 'assign' because 'replace' was giving strange Back button behavior
+                window.location.assign(data.redirect);
+              }
+
               $(".loading").remove();
               // remove invisible and add back visible, so we aren't left with
               // a div with an empty class attribute
diff --git a/benefits/enrollment/urls.py b/benefits/enrollment/urls.py
index 22398bc98..446cf6ae4 100644
--- a/benefits/enrollment/urls.py
+++ b/benefits/enrollment/urls.py
@@ -14,4 +14,5 @@
     path("token", views.token, name="token"),
     path("retry", views.retry, name="retry"),
     path("success", views.success, name="success"),
+    path("system_error", views.system_error, name="system_error"),
 ]
diff --git a/benefits/enrollment/views.py b/benefits/enrollment/views.py
index 4c23fa783..00831ffae 100644
--- a/benefits/enrollment/views.py
+++ b/benefits/enrollment/views.py
@@ -10,6 +10,7 @@
 from django.utils.decorators import decorator_from_middleware
 from littlepay.api.client import Client
 from requests.exceptions import HTTPError
+import sentry_sdk
 
 from benefits.core import session
 from benefits.core.middleware import (
@@ -24,6 +25,7 @@
 ROUTE_INDEX = "enrollment:index"
 ROUTE_RETRY = "enrollment:retry"
 ROUTE_SUCCESS = "enrollment:success"
+ROUTE_SYSTEM_ERROR = "enrollment:system_error"
 ROUTE_TOKEN = "enrollment:token"
 
 TEMPLATE_RETRY = "enrollment/retry.html"
@@ -47,8 +49,20 @@ def token(request):
             audience=payment_processor.audience,
         )
         client.oauth.ensure_active_token(client.token)
-        response = client.request_card_tokenization_access()
-        session.update(request, enrollment_token=response.get("access_token"), enrollment_token_exp=response.get("expires_at"))
+
+        try:
+            response = client.request_card_tokenization_access()
+        except Exception as e:
+            if isinstance(e, HTTPError) and e.response.status_code >= 500:
+                sentry_sdk.capture_exception(e)
+                data = {"redirect": reverse(ROUTE_SYSTEM_ERROR)}
+                return JsonResponse(data)
+            else:
+                raise e
+        else:
+            session.update(
+                request, enrollment_token=response.get("access_token"), enrollment_token_exp=response.get("expires_at")
+            )
 
     data = {"token": session.enrollment_token(request)}
 
diff --git a/tests/pytest/enrollment/test_views.py b/tests/pytest/enrollment/test_views.py
index f853ecbfc..39d2170d9 100644
--- a/tests/pytest/enrollment/test_views.py
+++ b/tests/pytest/enrollment/test_views.py
@@ -12,6 +12,7 @@
     ROUTE_INDEX,
     ROUTE_TOKEN,
     ROUTE_SUCCESS,
+    ROUTE_SYSTEM_ERROR,
     ROUTE_RETRY,
     TEMPLATE_SUCCESS,
     TEMPLATE_SYSTEM_ERROR,
@@ -99,6 +100,31 @@ def test_token_valid(mocker, client):
     assert data["token"] == "enrollment_token"
 
 
+@pytest.mark.django_db
+@pytest.mark.usefixtures("mocked_session_agency", "mocked_session_eligibility")
+def test_token_http_error_500(mocker, client):
+    mocker.patch("benefits.core.session.enrollment_token_valid", return_value=False)
+
+    mock_client_cls = mocker.patch("benefits.enrollment.views.Client")
+    mock_client = mock_client_cls.return_value
+
+    mock_error = {"message": "Mock error message"}
+    mock_error_response = mocker.Mock(status_code=500, **mock_error)
+    mock_error_response.json.return_value = mock_error
+    mock_client.request_card_tokenization_access.side_effect = HTTPError(
+        response=mock_error_response,
+    )
+
+    path = reverse(ROUTE_TOKEN)
+    response = client.get(path)
+
+    assert response.status_code == 200
+    data = response.json()
+    assert "token" not in data
+    assert "redirect" in data
+    assert data["redirect"] == reverse(ROUTE_SYSTEM_ERROR)
+
+
 @pytest.mark.django_db
 @pytest.mark.usefixtures("mocked_session_agency", "mocked_session_verifier", "mocked_session_eligibility")
 def test_index_eligible_get(client, model_EligibilityType):