diff --git a/tests/document/indexes.py b/tests/document/indexes.py
index 6256cde3..b1ea3707 100644
--- a/tests/document/indexes.py
+++ b/tests/document/indexes.py
@@ -432,6 +432,7 @@ class IndexesTest(unittest.TestCase):
 
         class Test(Document):
             a = IntField()
+            b = IntField()
 
             meta = {
                 'indexes': ['a'],
@@ -446,13 +447,30 @@ class IndexesTest(unittest.TestCase):
         # Need to be explicit about covered indexes as mongoDB doesn't know if
         # the documents returned might have more keys in that here.
         query_plan = Test.objects(id=obj.id).exclude('a').explain()
-        self.assertFalse(query_plan['indexOnly'])
+        if pymongo.version_tuple[0] < 3:
+            self.assertFalse(query_plan['indexOnly'])
+        else:
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('inputStage').get('stage'), 'IDHACK')
 
         query_plan = Test.objects(id=obj.id).only('id').explain()
-        self.assertTrue(query_plan['indexOnly'])
+        if pymongo.version_tuple[0] < 3:
+            self.assertTrue(query_plan['indexOnly'])
+        else:
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('inputStage').get('stage'), 'IDHACK')
 
         query_plan = Test.objects(a=1).only('a').exclude('id').explain()
-        self.assertTrue(query_plan['indexOnly'])
+        if pymongo.version_tuple[0] < 3:
+            self.assertTrue(query_plan['indexOnly'])
+        else:
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('inputStage').get('stage'), 'IXSCAN')
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('stage'), 'PROJECTION')
+
+        query_plan = Test.objects(a=1).explain()
+        if pymongo.version_tuple[0] < 3:
+            self.assertFalse(query_plan['indexOnly'])
+        else:
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('inputStage').get('stage'), 'IXSCAN')
+            self.assertEqual(query_plan.get('queryPlanner').get('winningPlan').get('stage'), 'FETCH')
 
     def test_index_on_id(self):
 
@@ -491,6 +509,9 @@ class IndexesTest(unittest.TestCase):
 
         self.assertEqual(BlogPost.objects.count(), 10)
         self.assertEqual(BlogPost.objects.hint().count(), 10)
+        # here we seem to have find a bug in PyMongo 3.
+        # The cursor first makes a SON out of the list of tuples
+        # Then later reuses it and wonders why is it not a list of tuples
         self.assertEqual(BlogPost.objects.hint([('tags', 1)]).count(), 10)
 
         self.assertEqual(BlogPost.objects.hint([('ZZ', 1)]).count(), 10)