Move test directory, add TxRequest

* ./tests is moved to ./trading/tests
* Remove trading/tests.py
* Add TxRequest model
* Add tests for TxRequests

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

trading/tests/test_models.py

@@ -0,0 +1,107 @@
+from django.test import TestCase
+from trading.models import User, Commodity, Tx, TxRequest, BalanceError
+
+
+class TestTransactions(TestCase):
+    def test_user_balances(self):
+        # Create users
+        user1 = User.objects.create_user(username="test1", email="test1@test.test")
+        user2 = User.objects.create_user(username="test2", email="test2@test.test")
+
+        # Create test commodity
+        commodity = Commodity(created_by=user1, in_circulation=1000, name="commodity")
+        commodity.save()
+
+        # Confirm balances
+        self.assertEqual(user1.balances(), {commodity: 1000})
+        self.assertEqual(user1.balance_of(commodity), 1000)
+        self.assertEqual(user2.balances(), {})
+        self.assertEqual(user2.balance_of(commodity), 0)
+
+        # Create transaction
+        Tx(source=user1, dest=user2, amount=100, commodity=commodity).save()
+
+        # Confirm balances
+        self.assertEqual(user1.balances(), {commodity: 900})
+        self.assertEqual(user2.balances(), {commodity: 100})
+
+        # Ensure we can't trade when there's missing balance
+        with self.assertRaises(BalanceError):
+            Tx(source=user2, dest=user1, amount=1000, commodity=commodity).save()
+
+        # Confirm balances
+        self.assertEqual(user1.balances(), {commodity: 900})
+        self.assertEqual(user2.balances(), {commodity: 100})
+
+    def test_tx_requests(self):
+        # Create users
+        user1 = User.objects.create_user(username="test1", email="test1@test.test")
+        user2 = User.objects.create_user(username="test2", email="test2@test.test")
+
+        # Create test commodity for user1
+        com1 = Commodity(created_by=user1, in_circulation=1000, name="test1")
+        com1.save()
+
+        # Create test commodity for user2
+        com2 = Commodity(created_by=user2, in_circulation=1000, name="test2")
+        com2.save()
+
+        # Create TX request
+        req1 = TxRequest.open(user1, user2, com1, com2, 10, 10)
+
+        # Confirm balances
+        self.assertEqual(user1.balance_of(com1), 990)
+        self.assertEqual(user1.balance_of(com2), 0)
+        self.assertEqual(user2.balance_of(com1), 0)
+        self.assertEqual(user2.balance_of(com2), 1000)
+
+        # Accept TX request
+        req1.accept()
+
+        # Confirm balances
+        self.assertEqual(user1.balance_of(com1), 990)
+        self.assertEqual(user1.balance_of(com2), 10)
+        self.assertEqual(user2.balance_of(com1), 10)
+        self.assertEqual(user2.balance_of(com2), 990)
+
+        # Create TX request 
+        req2 = TxRequest.open(user2, user1, com2, com1, 10, 10)
+
+        # Confirm balances
+        self.assertEqual(user1.balance_of(com1), 990)
+        self.assertEqual(user1.balance_of(com2), 10)
+        self.assertEqual(user2.balance_of(com1), 10)
+        self.assertEqual(user2.balance_of(com2), 980)
+
+        # Decline TX request
+        req2.decline()
+
+        # Confirm balances
+        self.assertEqual(user1.balance_of(com1), 990)
+        self.assertEqual(user1.balance_of(com2), 10)
+        self.assertEqual(user2.balance_of(com1), 10)
+        self.assertEqual(user2.balance_of(com2), 990)
+
+        # Ensure assertions on already created TXs
+        with self.assertRaises(AssertionError):
+            req1.accept()
+        with self.assertRaises(AssertionError):
+            req1.decline()
+        with self.assertRaises(AssertionError):
+            req2.accept()
+        with self.assertRaises(AssertionError):
+            req2.decline()
+
+        # Balance checking
+        # Ensure whoever opens the request has the balance available
+        with self.assertRaises(BalanceError):
+            TxRequest.open(user1, user2, com2, com1, 100, 100)
+
+        # Ensure whoever tries to accept the request has the balance available
+        req3 = TxRequest.open(user1, user2, com2, com1, 10, 100)
+        with self.assertRaises(BalanceError):
+            req3.accept()
+
+        # And make sure you can still decline it after failing to accept it.
+        req3.decline()
+