Add finance app with Stripe Checkout subscriptions (#21) (#23)

## Summary - Closes #21 — new Django `finance` app with Stripe as payment provider - Subscription price defaults to **$10 USD / month** via `SUBSCRIPTION_PRICE_AMOUNT_CENTS = 1000` in `settings.py` (env-overridable) - Persists **Invoice** and **Payment** rows; both registered in Django admin (with payment inline on invoices) - Checkout Session API redirects users to Stripe hosted payment; webhook verifies signatures and upserts ledger idempotently ## API - `POST /api/finance/checkout/` — JWT auth → `{ checkout_url, session_id }` - `GET /api/finance/invoices/` / `GET /api/finance/payments/` — own records - `POST /api/finance/webhooks/stripe/` — Stripe signature-verified webhook ## Config Documented in `.env.example` / `.env.prod.example`: `STRIPE_SECRET_KEY`, `STRIPE_PUBLISHABLE_KEY`, `STRIPE_WEBHOOK_SECRET`, optional `STRIPE_PRICE_ID`, `FRONTEND_BASE_URL` ## Test plan - [x] `uv run python manage.py test finance` (17 tests) - [ ] Set Stripe test keys locally; create checkout session; complete payment in Stripe test mode - [ ] Confirm Invoice/Payment appear in `/admin/` - [ ] Point Stripe webhook to `/api/finance/webhooks/stripe/` and verify `checkout.session.completed` / `invoice.paid`Reviewed-on: #23
2026-07-26 17:35:06 -07:00
parent 9984d1c340
commit ad44359804
23 changed files with 1540 additions and 0 deletions
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+"""Tests for Stripe Checkout Session API (mocked Stripe SDK)."""
+
+from unittest.mock import MagicMock, patch
+
+from django.test import override_settings
+from django.urls import reverse
+from rest_framework import status
+from rest_framework.test import APITestCase
+
+from chat_backend.tests.factories import make_company, make_user
+from finance.models import Invoice
+
+
+class CreateCheckoutSessionViewTestCase(APITestCase):
+    def setUp(self):
+        self.company = make_company()
+        self.user = make_user(company=self.company)
+        self.client.force_authenticate(user=self.user)
+        self.url = reverse("finance_checkout")
+
+    @override_settings(
+        STRIPE_SECRET_KEY="sk_test_fake",
+        SUBSCRIPTION_PRICE_AMOUNT_CENTS=1000,
+        SUBSCRIPTION_PRICE_CURRENCY="usd",
+        SUBSCRIPTION_PRICE_INTERVAL="month",
+        SUBSCRIPTION_PRODUCT_NAME="Chat Subscription",
+        STRIPE_PRICE_ID="",
+        STRIPE_CHECKOUT_SUCCESS_URL="http://localhost:3000/ok",
+        STRIPE_CHECKOUT_CANCEL_URL="http://localhost:3000/cancel",
+    )
+    @patch("finance.services.stripe_service.stripe.checkout.Session.create")
+    def test_creates_checkout_session_and_draft_invoice(self, mock_create):
+        mock_session = MagicMock()
+        mock_session.id = "cs_test_abc"
+        mock_session.url = "https://checkout.stripe.com/c/pay/cs_test_abc"
+        mock_session.customer = None
+        mock_create.return_value = mock_session
+
+        response = self.client.post(self.url, {}, format="json")
+
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        self.assertEqual(
+            response.data["checkout_url"],
+            "https://checkout.stripe.com/c/pay/cs_test_abc",
+        )
+        self.assertEqual(response.data["session_id"], "cs_test_abc")
+
+        mock_create.assert_called_once()
+        kwargs = mock_create.call_args.kwargs
+        self.assertEqual(kwargs["mode"], "subscription")
+        line_item = kwargs["line_items"][0]
+        self.assertEqual(line_item["price_data"]["unit_amount"], 1000)
+        self.assertEqual(line_item["price_data"]["currency"], "usd")
+        self.assertEqual(
+            line_item["price_data"]["recurring"]["interval"], "month"
+        )
+        self.assertEqual(kwargs["metadata"]["user_id"], str(self.user.pk))
+
+        invoice = Invoice.objects.get(stripe_checkout_session_id="cs_test_abc")
+        self.assertEqual(invoice.user, self.user)
+        self.assertEqual(invoice.company, self.company)
+        self.assertEqual(invoice.amount_due, 1000)
+        self.assertEqual(invoice.status, Invoice.Status.OPEN)
+
+    @override_settings(STRIPE_SECRET_KEY="", STRIPE_PRICE_ID="")
+    def test_missing_stripe_key_returns_503(self):
+        response = self.client.post(self.url, {}, format="json")
+        self.assertEqual(response.status_code, status.HTTP_503_SERVICE_UNAVAILABLE)
+
+    def test_unauthenticated_rejected(self):
+        self.client.force_authenticate(user=None)
+        response = self.client.post(self.url, {}, format="json")
+        self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
+
+    @override_settings(
+        STRIPE_SECRET_KEY="sk_test_fake",
+        STRIPE_PRICE_ID="price_abc123",
+        STRIPE_CHECKOUT_SUCCESS_URL="http://localhost:3000/ok",
+        STRIPE_CHECKOUT_CANCEL_URL="http://localhost:3000/cancel",
+    )
+    @patch("finance.services.stripe_service.stripe.checkout.Session.create")
+    def test_uses_stripe_price_id_when_set(self, mock_create):
+        mock_session = MagicMock()
+        mock_session.id = "cs_test_price"
+        mock_session.url = "https://checkout.stripe.com/c/pay/cs_test_price"
+        mock_session.customer = None
+        mock_create.return_value = mock_session
+
+        response = self.client.post(self.url, {}, format="json")
+        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        line_item = mock_create.call_args.kwargs["line_items"][0]
+        self.assertEqual(line_item, {"price": "price_abc123", "quantity": 1})
+
+
+class InvoicePaymentListViewTestCase(APITestCase):
+    def setUp(self):
+        self.company = make_company()
+        self.user = make_user(company=self.company)
+        self.other = make_user(
+            email="other@test.com",
+            username="other@test.com",
+            company=self.company,
+        )
+        self.client.force_authenticate(user=self.user)
+        Invoice.objects.create(
+            user=self.user,
+            company=self.company,
+            amount_due=1000,
+            stripe_checkout_session_id="cs_mine",
+        )
+        Invoice.objects.create(
+            user=self.other,
+            company=self.company,
+            amount_due=1000,
+            stripe_checkout_session_id="cs_other",
+        )
+
+    def test_list_own_invoices_only(self):
+        response = self.client.get(reverse("finance_invoices"))
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(len(response.data), 1)
+        self.assertEqual(response.data[0]["stripe_checkout_session_id"], "cs_mine")