Replace assertEqual(None, *) with assertIsNone in tests

Replace assertEqual(None, *) with assertIsNone in tests to have
more clear messages in case of failure.

Change-Id: I2732b3e747bd9394f9add7f1b077b366864fddd7
Closes-Bug:#1280522
diff --git a/tempest/api/compute/admin/test_aggregates.py b/tempest/api/compute/admin/test_aggregates.py
index 08d8a0d..4818aa6 100644
--- a/tempest/api/compute/admin/test_aggregates.py
+++ b/tempest/api/compute/admin/test_aggregates.py
@@ -47,7 +47,7 @@
         resp, aggregate = self.client.create_aggregate(name=aggregate_name)
         self.assertEqual(200, resp.status)
         self.assertEqual(aggregate_name, aggregate['name'])
-        self.assertEqual(None, aggregate['availability_zone'])
+        self.assertIsNone(aggregate['availability_zone'])
 
         resp, _ = self.client.delete_aggregate(aggregate['id'])
         self.assertEqual(200, resp.status)
@@ -175,7 +175,7 @@
         self.assertEqual(1, len(aggs))
         agg = aggs[0]
         self.assertEqual(aggregate_name, agg['name'])
-        self.assertEqual(None, agg['availability_zone'])
+        self.assertIsNone(agg['availability_zone'])
         self.assertIn(self.host, agg['hosts'])
 
     @attr(type='gate')
@@ -190,7 +190,7 @@
 
         resp, body = self.client.get_aggregate(aggregate['id'])
         self.assertEqual(aggregate_name, body['name'])
-        self.assertEqual(None, body['availability_zone'])
+        self.assertIsNone(body['availability_zone'])
         self.assertIn(self.host, body['hosts'])
 
     @attr(type='gate')
diff --git a/tempest/api/compute/v3/admin/test_aggregates.py b/tempest/api/compute/v3/admin/test_aggregates.py
index b8b478d..ed4b411 100644
--- a/tempest/api/compute/v3/admin/test_aggregates.py
+++ b/tempest/api/compute/v3/admin/test_aggregates.py
@@ -48,7 +48,7 @@
         resp, aggregate = self.client.create_aggregate(name=aggregate_name)
         self.assertEqual(201, resp.status)
         self.assertEqual(aggregate_name, aggregate['name'])
-        self.assertEqual(None, aggregate['availability_zone'])
+        self.assertIsNone(aggregate['availability_zone'])
 
         resp, _ = self.client.delete_aggregate(aggregate['id'])
         self.assertEqual(204, resp.status)
@@ -177,7 +177,7 @@
         self.assertEqual(1, len(aggs))
         agg = aggs[0]
         self.assertEqual(aggregate_name, agg['name'])
-        self.assertEqual(None, agg['availability_zone'])
+        self.assertIsNone(agg['availability_zone'])
         self.assertIn(self.host, agg['hosts'])
 
     @test.attr(type='gate')
@@ -192,7 +192,7 @@
 
         resp, body = self.client.get_aggregate(aggregate['id'])
         self.assertEqual(aggregate_name, body['name'])
-        self.assertEqual(None, body['availability_zone'])
+        self.assertIsNone(body['availability_zone'])
         self.assertIn(self.host, body['hosts'])
 
     @test.attr(type='gate')
diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index 0fc304a..9988e45 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -702,7 +702,7 @@
         :param floating_ip: type DeletableFloatingIp
         """
         floating_ip.update(port_id=None)
-        self.assertEqual(None, floating_ip.port_id)
+        self.assertIsNone(floating_ip.port_id)
         return floating_ip
 
     def _ping_ip_address(self, ip_address, should_succeed=True):
diff --git a/tempest/thirdparty/boto/test_ec2_keys.py b/tempest/thirdparty/boto/test_ec2_keys.py
index 329ace3..f26cd36 100644
--- a/tempest/thirdparty/boto/test_ec2_keys.py
+++ b/tempest/thirdparty/boto/test_ec2_keys.py
@@ -49,7 +49,7 @@
         key_name = data_utils.rand_name("keypair-")
         self.client.create_key_pair(key_name)
         self.client.delete_key_pair(key_name)
-        self.assertEqual(None, self.client.get_key_pair(key_name))
+        self.assertIsNone(self.client.get_key_pair(key_name))
 
     @attr(type='smoke')
     def test_get_ec2_keypair(self):