From 2fbe789090861dabf5c7c0481995c378fbaf4e8b Mon Sep 17 00:00:00 2001
From: Christopher Neugebauer <chrisjrn@gmail.com>
Date: Thu, 7 Apr 2016 18:26:31 +1000
Subject: [PATCH] =?UTF-8?q?Adds=20validate=5Fallowed=5Fto=5Fpay(),=20which?=
 =?UTF-8?q?=20validates=20whether=20you=E2=80=99re=20allowed=20to=20pay=20?=
 =?UTF-8?q?for=20an=20invoice?=
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---
 registrasion/controllers/invoice.py      | 24 ++++++++++++++++++++++++
 registrasion/tests/controller_helpers.py | 11 +----------
 registrasion/tests/test_cart.py          |  4 ++++
 registrasion/tests/test_invoice.py       | 17 +++++++++++++++--
 4 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/registrasion/controllers/invoice.py b/registrasion/controllers/invoice.py
index f7ae13e5..c5a527ca 100644
--- a/registrasion/controllers/invoice.py
+++ b/registrasion/controllers/invoice.py
@@ -126,6 +126,30 @@ class InvoiceController(object):
 
         return invoice
 
+    def _refresh(self):
+        ''' Refreshes the underlying invoice and cart objects. '''
+        self.invoice.refresh_from_db()
+        if self.invoice.cart:
+            self.invoice.cart.refresh_from_db()
+
+    def validate_allowed_to_pay(self):
+        ''' Passes cleanly if we're allowed to pay, otherwise raise
+        a ValidationError. '''
+
+        self._refresh()
+
+        if not self.invoice.is_unpaid:
+            raise ValidationError("You can only pay for unpaid invoices.")
+
+        if not self.invoice.cart:
+            return
+
+        if not self._invoice_matches_cart():
+            raise ValidationError("The registration has been amended since "
+                                  "generating this invoice.")
+
+        CartController(self.invoice.cart).validate_cart()
+
     def total_payments(self):
         ''' Returns the total amount paid towards this invoice. '''
 
diff --git a/registrasion/tests/controller_helpers.py b/registrasion/tests/controller_helpers.py
index 60cf2346..476351dd 100644
--- a/registrasion/tests/controller_helpers.py
+++ b/registrasion/tests/controller_helpers.py
@@ -37,17 +37,8 @@ class TestingInvoiceController(InvoiceController):
     def pay(self, reference, amount):
         ''' Testing method for simulating an invoice paymenht by the given
         amount. '''
-        if self.invoice.cart:
-            cart = CartController(self.invoice.cart)
-            cart.validate_cart()  # Raises ValidationError if invalid
 
-        status = self.invoice.status
-        if status == rego.Invoice.STATUS_VOID:
-            raise ValidationError("Void invoices cannot be paid")
-        elif status == rego.Invoice.STATUS_PAID:
-            raise ValidationError("Paid invoices cannot be paid again")
-        elif status == rego.Invoice.STATUS_REFUNDED:
-            raise ValidationError("Refunded invoices cannot be paid")
+        self.validate_allowed_to_pay()
 
         ''' Adds a payment '''
         payment = rego.ManualPayment.objects.create(
diff --git a/registrasion/tests/test_cart.py b/registrasion/tests/test_cart.py
index e87ef37e..f8a82c21 100644
--- a/registrasion/tests/test_cart.py
+++ b/registrasion/tests/test_cart.py
@@ -148,6 +148,10 @@ class RegistrationCartTestCase(SetTimeMixin, TestCase):
         voucher.save()
         return voucher
 
+    @classmethod
+    def reget(cls, object):
+        return type(object).objects.get(id=object.id)
+
 
 class BasicCartTests(RegistrationCartTestCase):
 
diff --git a/registrasion/tests/test_invoice.py b/registrasion/tests/test_invoice.py
index 645dfb80..b121bfa1 100644
--- a/registrasion/tests/test_invoice.py
+++ b/registrasion/tests/test_invoice.py
@@ -180,7 +180,7 @@ class InvoiceTestCase(RegistrationCartTestCase):
         invoice_1.void()
 
         with self.assertRaises(ValidationError):
-            invoice_1.pay("Reference", invoice_1.invoice.value)
+            invoice_1.validate_allowed_to_pay()
 
     def test_cannot_void_paid_invoice(self):
         current_cart = TestingCartController.for_user(self.USER_1)
@@ -199,9 +199,22 @@ class InvoiceTestCase(RegistrationCartTestCase):
         with self.assertRaises(ValidationError):
             invoice_1 = TestingInvoiceController.for_cart(current_cart.cart)
 
+    def test_cannot_pay_implicitly_void_invoice(self):
+        cart = TestingCartController.for_user(self.USER_1)
+        cart.add_to_cart(self.PROD_1, 1)
+        invoice = TestingInvoiceController.for_cart(self.reget(cart.cart))
+
+        # Implicitly void the invoice
+        cart.add_to_cart(self.PROD_1, 1)
+
+        with self.assertRaises(ValidationError):
+            invoice.validate_allowed_to_pay()
+
+
+
     # TODO: test partially paid invoice cannot be void until payments
     # are refunded
 
     # TODO: test overpaid invoice results in credit note
 
-    # TODO: test credit note generation more generally 
+    # TODO: test credit note generation more generally