refactor(enrollment): extract logic handling POST requests to enrollment

reuse it in the `in_person.enrollment` view.

this gets us back to having a working form submission in the in-person
enrollment view, but we need to be able to configure which templates
to return for the various success / error scenarios.

benefits/enrollment/views.py

@@ -81,45 +81,83 @@ def index(request):
 
     # POST back after transit processor form, process card token
     if request.method == "POST":
-        form = forms.CardTokenizeSuccessForm(request.POST)
-        if not form.is_valid():
-            raise Exception("Invalid card token form")
+        return enrollment_post(request, agency, flow)
 
-        card_token = form.cleaned_data.get("card_token")
+    # GET enrollment index
+    else:
+        tokenize_retry_form = forms.CardTokenizeFailForm(routes.ENROLLMENT_RETRY, "form-card-tokenize-fail-retry")
+        tokenize_server_error_form = forms.CardTokenizeFailForm(routes.SERVER_ERROR, "form-card-tokenize-fail-server-error")
+        tokenize_system_error_form = forms.CardTokenizeFailForm(
+            routes.ENROLLMENT_SYSTEM_ERROR, "form-card-tokenize-fail-system-error"
+        )
+        tokenize_success_form = forms.CardTokenizeSuccessForm(routes.ENROLLMENT_INDEX, auto_id=True, label_suffix="")
 
-        client = Client(
-            base_url=agency.transit_processor.api_base_url,
-            client_id=agency.transit_processor_client_id,
-            client_secret=agency.transit_processor_client_secret,
-            audience=agency.transit_processor_audience,
+        context = enrollment_get_context(
+            request,
+            agency,
+            tokenize_retry_form=tokenize_retry_form,
+            tokenize_server_error_form=tokenize_server_error_form,
+            tokenize_system_error_form=tokenize_system_error_form,
+            tokenize_success_form=tokenize_success_form,
         )
-        client.oauth.ensure_active_token(client.token)
+        logger.debug(f'card_tokenize_url: {context["card_tokenize_url"]}')
 
-        funding_source = client.get_funding_source_by_token(card_token)
-        group_id = flow.group_id
+        return TemplateResponse(request, flow.enrollment_index_template, context)
 
-        try:
-            group_funding_source = _get_group_funding_source(
-                client=client, group_id=group_id, funding_source_id=funding_source.id
-            )
 
-            already_enrolled = group_funding_source is not None
+def enrollment_post(request, agency, flow):
+    """Processes the card token returned from transit processor form."""
+    form = forms.CardTokenizeSuccessForm(request.POST)
+    if not form.is_valid():
+        raise Exception("Invalid card token form")
 
-            if flow.supports_expiration:
-                # set expiry on session
-                if already_enrolled and group_funding_source.expiry_date is not None:
-                    session.update(request, enrollment_expiry=group_funding_source.expiry_date)
-                else:
-                    session.update(request, enrollment_expiry=_calculate_expiry(flow.expiration_days))
+    card_token = form.cleaned_data.get("card_token")
+
+    client = Client(
+        base_url=agency.transit_processor.api_base_url,
+        client_id=agency.transit_processor_client_id,
+        client_secret=agency.transit_processor_client_secret,
+        audience=agency.transit_processor_audience,
+    )
+    client.oauth.ensure_active_token(client.token)
+
+    funding_source = client.get_funding_source_by_token(card_token)
+    group_id = flow.group_id
+
+    try:
+        group_funding_source = _get_group_funding_source(client=client, group_id=group_id, funding_source_id=funding_source.id)
 
-                if not already_enrolled:
-                    # enroll user with an expiration date, return success
-                    client.link_concession_group_funding_source(
-                        group_id=group_id, funding_source_id=funding_source.id, expiry=session.enrollment_expiry(request)
+        already_enrolled = group_funding_source is not None
+
+        if flow.supports_expiration:
+            # set expiry on session
+            if already_enrolled and group_funding_source.expiry_date is not None:
+                session.update(request, enrollment_expiry=group_funding_source.expiry_date)
+            else:
+                session.update(request, enrollment_expiry=_calculate_expiry(flow.expiration_days))
+
+            if not already_enrolled:
+                # enroll user with an expiration date, return success
+                client.link_concession_group_funding_source(
+                    group_id=group_id, funding_source_id=funding_source.id, expiry=session.enrollment_expiry(request)
+                )
+                return success(request)
+            else:  # already_enrolled
+                if group_funding_source.expiry_date is None:
+                    # update expiration of existing enrollment, return success
+                    client.update_concession_group_funding_source_expiry(
+                        group_id=group_id,
+                        funding_source_id=funding_source.id,
+                        expiry=session.enrollment_expiry(request),
                     )
                     return success(request)
-                else:  # already_enrolled
-                    if group_funding_source.expiry_date is None:
+                else:
+                    is_expired = _is_expired(group_funding_source.expiry_date)
+                    is_within_reenrollment_window = _is_within_reenrollment_window(
+                        group_funding_source.expiry_date, session.enrollment_reenrollment(request)
+                    )
+
+                    if is_expired or is_within_reenrollment_window:
                         # update expiration of existing enrollment, return success
                         client.update_concession_group_funding_source_expiry(
                             group_id=group_id,
@@ -128,68 +166,33 @@ def index(request):
                         )
                         return success(request)
                     else:
-                        is_expired = _is_expired(group_funding_source.expiry_date)
-                        is_within_reenrollment_window = _is_within_reenrollment_window(
-                            group_funding_source.expiry_date, session.enrollment_reenrollment(request)
-                        )
-
-                        if is_expired or is_within_reenrollment_window:
-                            # update expiration of existing enrollment, return success
-                            client.update_concession_group_funding_source_expiry(
-                                group_id=group_id,
-                                funding_source_id=funding_source.id,
-                                expiry=session.enrollment_expiry(request),
-                            )
-                            return success(request)
-                        else:
-                            # re-enrollment error, return enrollment error with expiration and reenrollment_date
-                            return reenrollment_error(request)
-            else:  # eligibility does not support expiration
-                if not already_enrolled:
-                    # enroll user with no expiration date, return success
-                    client.link_concession_group_funding_source(group_id=group_id, funding_source_id=funding_source.id)
+                        # re-enrollment error, return enrollment error with expiration and reenrollment_date
+                        return reenrollment_error(request)
+        else:  # eligibility does not support expiration
+            if not already_enrolled:
+                # enroll user with no expiration date, return success
+                client.link_concession_group_funding_source(group_id=group_id, funding_source_id=funding_source.id)
+                return success(request)
+            else:  # already_enrolled
+                if group_funding_source.expiry_date is None:
+                    # no action, return success
                     return success(request)
-                else:  # already_enrolled
-                    if group_funding_source.expiry_date is None:
-                        # no action, return success
-                        return success(request)
-                    else:
-                        # remove expiration date, return success
-                        raise NotImplementedError("Removing expiration date is currently not supported")
-
-        except HTTPError as e:
-            if e.response.status_code >= 500:
-                analytics.returned_error(request, str(e))
-                sentry_sdk.capture_exception(e)
+                else:
+                    # remove expiration date, return success
+                    raise NotImplementedError("Removing expiration date is currently not supported")
 
-                return system_error(request)
-            else:
-                analytics.returned_error(request, str(e))
-                raise Exception(f"{e}: {e.response.json()}")
-        except Exception as e:
+    except HTTPError as e:
+        if e.response.status_code >= 500:
             analytics.returned_error(request, str(e))
-            raise e
-
-    # GET enrollment index
-    else:
-        tokenize_retry_form = forms.CardTokenizeFailForm(routes.ENROLLMENT_RETRY, "form-card-tokenize-fail-retry")
-        tokenize_server_error_form = forms.CardTokenizeFailForm(routes.SERVER_ERROR, "form-card-tokenize-fail-server-error")
-        tokenize_system_error_form = forms.CardTokenizeFailForm(
-            routes.ENROLLMENT_SYSTEM_ERROR, "form-card-tokenize-fail-system-error"
-        )
-        tokenize_success_form = forms.CardTokenizeSuccessForm(routes.ENROLLMENT_INDEX, auto_id=True, label_suffix="")
-
-        context = enrollment_get_context(
-            request,
-            agency,
-            tokenize_retry_form=tokenize_retry_form,
-            tokenize_server_error_form=tokenize_server_error_form,
-            tokenize_system_error_form=tokenize_system_error_form,
-            tokenize_success_form=tokenize_success_form,
-        )
-        logger.debug(f'card_tokenize_url: {context["card_tokenize_url"]}')
+            sentry_sdk.capture_exception(e)
 
-        return TemplateResponse(request, flow.enrollment_index_template, context)
+            return system_error(request)
+        else:
+            analytics.returned_error(request, str(e))
+            raise Exception(f"{e}: {e.response.json()}")
+    except Exception as e:
+        analytics.returned_error(request, str(e))
+        raise e
 
 
 def enrollment_get_context(

benefits/in_person/views.py

@@ -3,7 +3,7 @@
 
 from benefits.core import session
 from benefits.enrollment import forms
-from benefits.enrollment.views import enrollment_get_context
+from benefits.enrollment.views import enrollment_get_context, enrollment_post
 from benefits.routes import routes
 
 
@@ -17,10 +17,11 @@ def eligibility(request):
 
 def enrollment(request):
     agency = session.agency(request)
+    flow = session.flow(request)
 
     # POST back after transit processor form, process card token
     if request.method == "POST":
-        pass
+        return enrollment_post(request, agency, flow)
     # GET enrollment page
     else:
         tokenize_retry_form = forms.CardTokenizeFailForm(routes.IN_PERSON_ENROLLMENT_RETRY, "form-card-tokenize-fail-retry")

tests/pytest/in_person/test_views.py

@@ -49,3 +49,12 @@ def test_enrollment_logged_in_get(admin_client):
     assert "form_retry" in response.context_data
     assert "form_success" in response.context_data
     assert "overlay_language" in response.context_data
+
+
+@pytest.mark.django_db
+@pytest.mark.usefixtures("mocked_session_agency", "mocked_session_flow")
+def test_enrollment_logged_in_post_invalid_form(admin_client, invalid_form_data):
+    path = reverse(routes.IN_PERSON_ENROLLMENT)
+
+    with pytest.raises(Exception, match=r"form"):
+        admin_client.post(path, invalid_form_data)