more thorough and isolated unit tests

tests/queryset/queryset.py

@@ -107,73 +107,110 @@ class QuerySetTest(unittest.TestCase):
 
     def test_find(self):
         """Ensure that a query returns a valid set of results."""
-        self.Person(name="User A", age=20).save()
-        self.Person(name="User B", age=30).save()
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
 
         # Find all people in the collection
         people = self.Person.objects
         self.assertEqual(people.count(), 2)
         results = list(people)
+
         self.assertTrue(isinstance(results[0], self.Person))
         self.assertTrue(isinstance(results[0].id, (ObjectId, str, unicode)))
-        self.assertEqual(results[0].name, "User A")
+
+        self.assertEqual(results[0], user_a)
+        self.assertEqual(results[0].name, 'User A')
         self.assertEqual(results[0].age, 20)
-        self.assertEqual(results[1].name, "User B")
+
+        self.assertEqual(results[1], user_b)
+        self.assertEqual(results[1].name, 'User B')
         self.assertEqual(results[1].age, 30)
 
-        # Use a query to filter the people found to just person1
+        # Filter people by age
         people = self.Person.objects(age=20)
         self.assertEqual(people.count(), 1)
         person = people.next()
+        self.assertEqual(person, user_a)
         self.assertEqual(person.name, "User A")
         self.assertEqual(person.age, 20)
 
-        # Test limit
+    def test_limit(self):
+        """Ensure that QuerySet.limit works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+
+        # Test limit on a new queryset
         people = list(self.Person.objects.limit(1))
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User A')
+        self.assertEqual(people[0], user_a)
 
         # Test limit on an existing queryset
         people = self.Person.objects
         self.assertEqual(len(people), 2)
-        self.assertEqual(len(people.limit(1)), 1)
+        people2 = people.limit(1)
+        self.assertEqual(len(people), 2)
+        self.assertEqual(len(people2), 1)
+        self.assertEqual(people2[0], user_a)
 
-        # Test skip
+        # Test chaining of only after limit
+        person = self.Person.objects().limit(1).only('name').first()
+        self.assertEqual(person, user_a)
+        self.assertEqual(person.name, 'User A')
+        self.assertEqual(person.age, None)
+
+    def test_skip(self):
+        """Ensure that QuerySet.skip works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+
+        # Test skip on a new queryset
         people = list(self.Person.objects.skip(1))
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User B')
+        self.assertEqual(people[0], user_b)
 
         # Test skip on an existing queryset
         people = self.Person.objects
         self.assertEqual(len(people), 2)
-        self.assertEqual(len(people.skip(1)), 1)
+        people2 = people.skip(1)
+        self.assertEqual(len(people), 2)
+        self.assertEqual(len(people2), 1)
+        self.assertEqual(people2[0], user_b)
 
-        person3 = self.Person(name="User C", age=40)
-        person3.save()
+        # Test chaining of only after skip
+        person = self.Person.objects().skip(1).only('name').first()
+        self.assertEqual(person, user_b)
+        self.assertEqual(person.name, 'User B')
+        self.assertEqual(person.age, None)
+
+    def test_slice(self):
+        """Ensure slicing a queryset works as expected."""
+        user_a = self.Person.objects.create(name='User A', age=20)
+        user_b = self.Person.objects.create(name='User B', age=30)
+        user_c = self.Person.objects.create(name="User C", age=40)
 
         # Test slice limit
         people = list(self.Person.objects[:2])
         self.assertEqual(len(people), 2)
-        self.assertEqual(people[0].name, 'User A')
-        self.assertEqual(people[1].name, 'User B')
+        self.assertEqual(people[0], user_a)
+        self.assertEqual(people[1], user_b)
 
         # Test slice skip
         people = list(self.Person.objects[1:])
         self.assertEqual(len(people), 2)
-        self.assertEqual(people[0].name, 'User B')
-        self.assertEqual(people[1].name, 'User C')
+        self.assertEqual(people[0], user_b)
+        self.assertEqual(people[1], user_c)
 
         # Test slice limit and skip
         people = list(self.Person.objects[1:2])
         self.assertEqual(len(people), 1)
-        self.assertEqual(people[0].name, 'User B')
+        self.assertEqual(people[0], user_b)
 
         # Test slice limit and skip on an existing queryset
         people = self.Person.objects
         self.assertEqual(len(people), 3)
         people2 = people[1:2]
         self.assertEqual(len(people2), 1)
-        self.assertEqual(people2[0].name, 'User B')
+        self.assertEqual(people2[0], user_b)
 
         # Test slice limit and skip cursor reset
         qs = self.Person.objects[1:2]
@@ -204,12 +241,6 @@ class QuerySetTest(unittest.TestCase):
         self.assertEqual("[<Person: Person object>, <Person: Person object>]",
                          "%s" % self.Person.objects[51:53])
 
-        # Test only after limit
-        self.assertEqual(self.Person.objects().limit(2).only('name')[0].age, None)
-
-        # Test only after skip
-        self.assertEqual(self.Person.objects().skip(2).only('name')[0].age, None)
-
     def test_find_one(self):
         """Ensure that a query using find_one returns a valid result.
         """