from django.test import TestCase
from trading.models import User, Commodity, Tx, 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")

        commodity = Commodity(created_by=user1, in_circulation=1000, name="commodity")
        commodity.save()

        self.assertEqual(user1.balances(), {commodity: 1000})
        self.assertEqual(user2.balances(), {})

        Tx(source=user1, dest=user2, amount=100, commodity=commodity).save()

        self.assertEqual(user1.balances(), {commodity: 900})
        self.assertEqual(user2.balances(), {commodity: 100})

        with self.assertRaises(BalanceError):
            Tx(source=user2, dest=user1, amount=1000, commodity=commodity).save()

        self.assertEqual(user1.balances(), {commodity: 900})
        self.assertEqual(user2.balances(), {commodity: 100})