from django.test import TestCase
from .models import Rental


class RentalTestCase(TestCase):

    def test_str(self):
        rental = Rental(name='Fitnessflow')
        self.assertEqual(rental.__str__(), 'Rental by Fitnessflow')

@@ -1,12 +1,28 @@
+import datetime%0A
 from django.
@@ -42,16 +42,67 @@
 estCase%0A
+from django.core.exceptions import ValidationError%0A
 from .mo
@@ -155,16 +155,696 @@
 Case):%0A%0A
+    def test_clean__valid_rental(self):%0A        rental = Rental(%0A            start_date=datetime.datetime(2017, 3, 15),%0A            return_date=datetime.datetime(2017, 3, 17)%0A        )%0A        rental.clean()%0A%0A    def test_clean__same_dates(self):%0A        rental = Rental(%0A            start_date=datetime.datetime(2017, 3, 15),%0A            return_date=datetime.datetime(2017, 3, 15)%0A        )%0A        rental.clean()%0A%0A    def test_clean__invalid_rental(self):%0A        rental = Rental(%0A            start_date=datetime.datetime(2017, 3, 15),%0A            return_date=datetime.datetime(2017, 3, 13)%0A        )%0A        with self.assertRaises(ValidationError):%0A            rental.clean()%0A%0A
     def 

Add test for constraint