diff --git a/releasenotes/notes/12.2.0-clients_module-16f3025f515bf9ec.yaml b/releasenotes/notes/12.2.0-clients_module-16f3025f515bf9ec.yaml
index 53741da..484d543 100644
--- a/releasenotes/notes/12.2.0-clients_module-16f3025f515bf9ec.yaml
+++ b/releasenotes/notes/12.2.0-clients_module-16f3025f515bf9ec.yaml
@@ -8,7 +8,7 @@
     access service clients defined in Tempest as well as service clients
     defined in all loaded plugins.
     The new ServiceClients class only exposes for now the service clients
-    which are in tempest.lib, i.e. compute, network and image. The remaing
+    which are in tempest.lib, i.e. compute, network and image. The remaining
     service clients (identity, volume and object-storage) will be added in
     future updates.
 deprecations:
diff --git a/tempest/api/compute/admin/test_agents.py b/tempest/api/compute/admin/test_agents.py
index 61359f1..40cb523 100644
--- a/tempest/api/compute/admin/test_agents.py
+++ b/tempest/api/compute/admin/test_agents.py
@@ -90,7 +90,8 @@
         body = self.client.create_agent(**self.params_agent)['agent']
         self.addCleanup(self.client.delete_agent, body['agent_id'])
         agents = self.client.list_agents()['agents']
-        self.assertTrue(len(agents) > 0, 'Cannot get any agents.(%s)' % agents)
+        self.assertGreater(len(agents), 0,
+                           'Cannot get any agents.(%s)' % agents)
         self.assertIn(body['agent_id'], map(lambda x: x['agent_id'], agents))
 
     @test.idempotent_id('eabadde4-3cd7-4ec4-a4b5-5a936d2d4408')
@@ -108,7 +109,8 @@
         agent_id_xen = agent_xen['agent_id']
         agents = (self.client.list_agents(hypervisor=agent_xen['hypervisor'])
                   ['agents'])
-        self.assertTrue(len(agents) > 0, 'Cannot get any agents.(%s)' % agents)
+        self.assertGreater(len(agents), 0,
+                           'Cannot get any agents.(%s)' % agents)
         self.assertIn(agent_id_xen, map(lambda x: x['agent_id'], agents))
         self.assertNotIn(body['agent_id'], map(lambda x: x['agent_id'],
                                                agents))
diff --git a/tempest/api/compute/admin/test_hosts.py b/tempest/api/compute/admin/test_hosts.py
index 29e1eb8..3797b29 100644
--- a/tempest/api/compute/admin/test_hosts.py
+++ b/tempest/api/compute/admin/test_hosts.py
@@ -28,7 +28,7 @@
     @test.idempotent_id('9bfaf98d-e2cb-44b0-a07e-2558b2821e4f')
     def test_list_hosts(self):
         hosts = self.client.list_hosts()['hosts']
-        self.assertTrue(len(hosts) >= 2, str(hosts))
+        self.assertGreaterEqual(len(hosts), 2, str(hosts))
 
     @test.idempotent_id('5dc06f5b-d887-47a2-bb2a-67762ef3c6de')
     def test_list_hosts_with_zone(self):
diff --git a/tempest/api/compute/admin/test_hypervisor.py b/tempest/api/compute/admin/test_hypervisor.py
index 92a9135..55134b1 100644
--- a/tempest/api/compute/admin/test_hypervisor.py
+++ b/tempest/api/compute/admin/test_hypervisor.py
@@ -31,7 +31,7 @@
         return hypers
 
     def assertHypervisors(self, hypers):
-        self.assertTrue(len(hypers) > 0, "No hypervisors found: %s" % hypers)
+        self.assertGreater(len(hypers), 0, "No hypervisors found: %s" % hypers)
 
     @test.idempotent_id('7f0ceacd-c64d-4e96-b8ee-d02943142cc5')
     def test_get_hypervisor_list(self):
diff --git a/tempest/api/compute/images/test_images_oneserver.py b/tempest/api/compute/images/test_images_oneserver.py
index 6c417f1..19e2880 100644
--- a/tempest/api/compute/images/test_images_oneserver.py
+++ b/tempest/api/compute/images/test_images_oneserver.py
@@ -45,35 +45,18 @@
         super(ImagesOneServerTestJSON, cls).setup_clients()
         cls.client = cls.compute_images_client
 
-    @classmethod
-    def resource_setup(cls):
-        super(ImagesOneServerTestJSON, cls).resource_setup()
-        server = cls.create_test_server(wait_until='ACTIVE')
-        cls.server_id = server['id']
-
     def _get_default_flavor_disk_size(self, flavor_id):
         flavor = self.flavors_client.show_flavor(flavor_id)['flavor']
         return flavor['disk']
 
-    @classmethod
-    def _rebuild_server_when_fails(cls, server_id):
-        try:
-            waiters.wait_for_server_status(cls.servers_client,
-                                           server_id, 'ACTIVE')
-        except Exception:
-            LOG.exception('server %s timed out to become ACTIVE. rebuilding'
-                          % server_id)
-            # Rebuild server if cannot reach the ACTIVE state
-            # Usually it means the server had a serious accident
-            cls.server_id = cls.rebuild_server(server_id)
-
     @test.idempotent_id('3731d080-d4c5-4872-b41a-64d0d0021314')
     def test_create_delete_image(self):
+        server_id = self.create_test_server(wait_until='ACTIVE')['id']
 
         # Create a new image
         name = data_utils.rand_name('image')
         meta = {'image_type': 'test'}
-        body = self.client.create_image(self.server_id, name=name,
+        body = self.client.create_image(server_id, name=name,
                                         metadata=meta)
         image_id = data_utils.parse_image_id(body.response['location'])
         self.addCleanup(test_utils.call_and_ignore_notfound_exc,
@@ -98,10 +81,11 @@
         # Verify the image was deleted correctly
         self.client.delete_image(image_id)
         self.client.wait_for_resource_deletion(image_id)
-        self.addCleanup(self._rebuild_server_when_fails, self.server_id)
 
     @test.idempotent_id('3b7c6fe4-dfe7-477c-9243-b06359db51e6')
     def test_create_image_specify_multibyte_character_image_name(self):
+        server_id = self.create_test_server(wait_until='ACTIVE')['id']
+
         # prefix character is:
         # http://www.fileformat.info/info/unicode/char/1F4A9/index.htm
 
@@ -109,7 +93,6 @@
         # #1370954 in glance which will 500 if mysql is used as the
         # backend and it attempts to store a 4 byte utf-8 character
         utf8_name = data_utils.rand_name('\xe2\x82\xa1')
-        body = self.client.create_image(self.server_id, name=utf8_name)
+        body = self.client.create_image(server_id, name=utf8_name)
         image_id = data_utils.parse_image_id(body.response['location'])
         self.addCleanup(self.client.delete_image, image_id)
-        self.addCleanup(self._rebuild_server_when_fails, self.server_id)
diff --git a/tempest/api/compute/keypairs/test_keypairs.py b/tempest/api/compute/keypairs/test_keypairs.py
index be6f615..562a508 100644
--- a/tempest/api/compute/keypairs/test_keypairs.py
+++ b/tempest/api/compute/keypairs/test_keypairs.py
@@ -57,8 +57,8 @@
         self.assertEqual(key_name, k_name,
                          "The created keypair name is not equal "
                          "to the requested name")
-        self.assertTrue(private_key is not None,
-                        "Field private_key is empty or not found.")
+        self.assertIsNotNone(private_key,
+                             "Field private_key is empty or not found.")
 
     @test.idempotent_id('a4233d5d-52d8-47cc-9a25-e1864527e3df')
     def test_get_keypair_detail(self):
@@ -72,8 +72,8 @@
                          "The created keypair name is not equal "
                          "to requested name")
         public_key = keypair_detail['public_key']
-        self.assertTrue(public_key is not None,
-                        "Field public_key is empty or not found.")
+        self.assertIsNotNone(public_key,
+                             "Field public_key is empty or not found.")
 
     @test.idempotent_id('39c90c6a-304a-49dd-95ec-2366129def05')
     def test_keypair_create_with_pub_key(self):
@@ -89,7 +89,7 @@
                    "XcPojYN56tI0OlrGqojbediJYD0rUsJu4weZpbn8vilb3JuDY+jws"
                    "snSA8wzBx3A/8y9Pp1B nova@ubuntu")
         keypair = self._create_keypair(k_name, pub_key)
-        self.assertFalse('private_key' in keypair,
+        self.assertNotIn('private_key', keypair,
                          "Field private_key is not empty!")
         key_name = keypair['name']
         self.assertEqual(key_name, k_name,
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 9077801..50910ec 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -131,8 +131,8 @@
                 server=server,
                 servers_client=self.client)
             new_boot_time = linux_client.get_boot_time()
-            self.assertTrue(new_boot_time > boot_time,
-                            '%s > %s' % (new_boot_time, boot_time))
+            self.assertGreater(new_boot_time, boot_time,
+                               '%s > %s' % (new_boot_time, boot_time))
 
     @test.attr(type='smoke')
     @test.idempotent_id('2cb1baf6-ac8d-4429-bf0d-ba8a0ba53e32')
@@ -458,8 +458,8 @@
 
             # NOTE: This test tries to get full length console log, and the
             # length should be bigger than the one of test_get_console_output.
-            self.assertTrue(lines > 10, "Cannot get enough console log length."
-                                        " (lines: %s)" % lines)
+            self.assertGreater(lines, 10, "Cannot get enough console log "
+                                          "length. (lines: %s)" % lines)
 
         self.wait_for(_check_full_length_console_log)
 
diff --git a/tempest/api/compute/volumes/test_volumes_get.py b/tempest/api/compute/volumes/test_volumes_get.py
index d599431..7549d4a 100644
--- a/tempest/api/compute/volumes/test_volumes_get.py
+++ b/tempest/api/compute/volumes/test_volumes_get.py
@@ -54,8 +54,8 @@
         self.assertEqual(volume['displayName'], v_name,
                          "The created volume name is not equal "
                          "to the requested name")
-        self.assertTrue(volume['id'] is not None,
-                        "Field volume id is empty or not found.")
+        self.assertIsNotNone(volume['id'],
+                             "Field volume id is empty or not found.")
         # Wait for Volume status to become ACTIVE
         waiters.wait_for_volume_status(self.client, volume['id'], 'available')
         # GET Volume
diff --git a/tempest/api/identity/admin/v2/test_services.py b/tempest/api/identity/admin/v2/test_services.py
index 3ed51f0..7973a03 100644
--- a/tempest/api/identity/admin/v2/test_services.py
+++ b/tempest/api/identity/admin/v2/test_services.py
@@ -38,7 +38,7 @@
         service_data = self.services_client.create_service(
             name=name, type=s_type,
             description=description)['OS-KSADM:service']
-        self.assertFalse(service_data['id'] is None)
+        self.assertIsNotNone(service_data['id'])
         self.addCleanup(self._del_service, service_data['id'])
         # Verifying response body of create service
         self.assertIn('id', service_data)
diff --git a/tempest/api/image/v1/test_images.py b/tempest/api/image/v1/test_images.py
index 7d52695..9fbdcd7 100644
--- a/tempest/api/image/v1/test_images.py
+++ b/tempest/api/image/v1/test_images.py
@@ -238,7 +238,7 @@
     def test_index_max_size(self):
         images_list = self.client.list_images(size_max=42)['images']
         for image in images_list:
-            self.assertTrue(image['size'] <= 42)
+            self.assertLessEqual(image['size'], 42)
         result_set = set(map(lambda x: x['id'], images_list))
         self.assertTrue(self.size42_set <= result_set)
         self.assertFalse(self.created_set - self.size42_set <= result_set)
@@ -261,7 +261,7 @@
         top_size = images_list[0]['size']  # We have non-zero sized images
         for image in images_list:
             size = image['size']
-            self.assertTrue(size <= top_size)
+            self.assertLessEqual(size, top_size)
             top_size = size
             self.assertEqual(image['status'], 'active')
 
diff --git a/tempest/api/image/v2/test_images.py b/tempest/api/image/v2/test_images.py
index 6f8d239..5cf8084 100644
--- a/tempest/api/image/v2/test_images.py
+++ b/tempest/api/image/v2/test_images.py
@@ -224,9 +224,10 @@
         image_size_list = map(lambda x: x['size'], images_list)
 
         for image_size in image_size_list:
-            self.assertTrue(image_size >= params['size_min'] and
-                            image_size <= params['size_max'],
-                            "Failed to get images by size_min and size_max")
+            self.assertGreaterEqual(image_size, params['size_min'],
+                                    "Failed to get images by size_min")
+            self.assertLessEqual(image_size, params['size_max'],
+                                 "Failed to get images by size_max")
 
     @test.idempotent_id('7fc9e369-0f58-4d05-9aa5-0969e2d59d15')
     def test_list_images_param_status(self):
diff --git a/tempest/api/object_storage/test_account_services.py b/tempest/api/object_storage/test_account_services.py
index 33e5852..eda4568 100644
--- a/tempest/api/object_storage/test_account_services.py
+++ b/tempest/api/object_storage/test_account_services.py
@@ -121,7 +121,7 @@
         self.assertHeaders(resp, 'Account', 'GET')
         self.assertIsNotNone(container_list)
         self.assertEqual(container_list.tag, 'account')
-        self.assertTrue('name' in container_list.keys())
+        self.assertIn('name', container_list.keys())
         self.assertEqual(container_list.find(".//container").tag, 'container')
         self.assertEqual(container_list.find(".//name").tag, 'name')
         self.assertEqual(container_list.find(".//count").tag, 'count')
@@ -209,7 +209,8 @@
                 self.account_client.list_account_containers(params=params)
             self.assertHeaders(resp, 'Account', 'GET')
 
-            self.assertTrue(len(container_list) <= limit, str(container_list))
+            self.assertLessEqual(len(container_list), limit,
+                                 str(container_list))
 
     @test.idempotent_id('888a3f0e-7214-4806-8e50-5e0c9a69bb5e')
     def test_list_containers_with_limit_and_end_marker(self):
diff --git a/tempest/api/object_storage/test_container_services.py b/tempest/api/object_storage/test_container_services.py
index dbe8b4a..9ce1b18 100644
--- a/tempest/api/object_storage/test_container_services.py
+++ b/tempest/api/object_storage/test_container_services.py
@@ -205,7 +205,7 @@
 
         self.assertIsNotNone(object_list)
         self.assertEqual(object_list.tag, 'container')
-        self.assertTrue('name' in object_list.keys())
+        self.assertIn('name', object_list.keys())
         self.assertEqual(object_list.find(".//object").tag, 'object')
         self.assertEqual(object_list.find(".//name").tag, 'name')
         self.assertEqual(object_list.find(".//hash").tag, 'hash')
diff --git a/tempest/api/orchestration/stacks/test_nova_keypair_resources.py b/tempest/api/orchestration/stacks/test_nova_keypair_resources.py
index 160bf6f..16d8180 100644
--- a/tempest/api/orchestration/stacks/test_nova_keypair_resources.py
+++ b/tempest/api/orchestration/stacks/test_nova_keypair_resources.py
@@ -83,7 +83,7 @@
                       output_map['KeyPairDontSavePrivate_PublicKey'])
         self.assertIn(u'KeyPairDontSavePrivate_PrivateKey', output_map)
         private_key = output_map['KeyPairDontSavePrivate_PrivateKey']
-        self.assertTrue(len(private_key) == 0)
+        self.assertEqual(0, len(private_key))
 
 
 class NovaKeyPairResourcesAWSTest(NovaKeyPairResourcesYAMLTest):
diff --git a/tempest/api/volume/admin/test_multi_backend.py b/tempest/api/volume/admin/test_multi_backend.py
index 120dbb1..5703313 100644
--- a/tempest/api/volume/admin/test_multi_backend.py
+++ b/tempest/api/volume/admin/test_multi_backend.py
@@ -129,7 +129,7 @@
         volume1_host = volume['os-vol-host-attr:host']
         msg = ("multi-backend reporting incorrect values for volume %s" %
                volume_id)
-        self.assertTrue(len(volume1_host.split("@")) > 1, msg)
+        self.assertGreater(len(volume1_host.split("@")), 1, msg)
 
     def _test_backend_name_distinction(self, volume_id_list):
         # this test checks that the volumes created at setUp don't
diff --git a/tempest/api/volume/admin/test_volume_hosts.py b/tempest/api/volume/admin/test_volume_hosts.py
index b58c525..f6de9a6 100644
--- a/tempest/api/volume/admin/test_volume_hosts.py
+++ b/tempest/api/volume/admin/test_volume_hosts.py
@@ -22,8 +22,8 @@
     @test.idempotent_id('d5f3efa2-6684-4190-9ced-1c2f526352ad')
     def test_list_hosts(self):
         hosts = self.admin_hosts_client.list_hosts()['hosts']
-        self.assertTrue(len(hosts) >= 2, "No. of hosts are < 2,"
-                        "response of list hosts is: % s" % hosts)
+        self.assertGreaterEqual(len(hosts), 2, "No. of hosts are < 2,"
+                                "response of list hosts is: % s" % hosts)
 
 
 class VolumeHostsAdminV1TestsJSON(VolumeHostsAdminV2TestsJSON):
diff --git a/tempest/api/volume/admin/test_volume_types.py b/tempest/api/volume/admin/test_volume_types.py
index 99f0a6b..eb6500c 100644
--- a/tempest/api/volume/admin/test_volume_types.py
+++ b/tempest/api/volume/admin/test_volume_types.py
@@ -102,8 +102,8 @@
         self.assertEqual(description, body['description'],
                          "The created volume_type_description name is "
                          "not equal to the requested name")
-        self.assertTrue(body['id'] is not None,
-                        "Field volume_type id is empty or not found.")
+        self.assertIsNotNone(body['id'],
+                             "Field volume_type id is empty or not found.")
         fetched_volume_type = self.admin_volume_types_client.show_volume_type(
             body['id'])['volume_type']
         self.assertEqual(name, fetched_volume_type['name'],
diff --git a/tempest/api/volume/test_volumes_get.py b/tempest/api/volume/test_volumes_get.py
index 07f799b..51de2be 100644
--- a/tempest/api/volume/test_volumes_get.py
+++ b/tempest/api/volume/test_volumes_get.py
@@ -54,8 +54,8 @@
         self.assertEqual(volume[self.name_field], v_name,
                          "The created volume name is not equal "
                          "to the requested name")
-        self.assertTrue(volume['id'] is not None,
-                        "Field volume id is empty or not found.")
+        self.assertIsNotNone(volume['id'],
+                             "Field volume id is empty or not found.")
         # Get Volume information
         fetched_volume = self.client.show_volume(volume['id'])['volume']
         self.assertEqual(v_name,
diff --git a/tempest/api/volume/v2/test_volumes_list.py b/tempest/api/volume/v2/test_volumes_list.py
index 60a35b0..7717027 100644
--- a/tempest/api/volume/v2/test_volumes_list.py
+++ b/tempest/api/volume/v2/test_volumes_list.py
@@ -73,11 +73,9 @@
             val0 = fetched_volume[0][sort_key]
             val1 = fetched_volume[1][sort_key]
             if sort_dir == 'asc':
-                self.assertTrue(val0 < val1,
-                                "%s < %s" % (val0, val1))
+                self.assertLess(val0, val1, "%s < %s" % (val0, val1))
             elif sort_dir == 'desc':
-                self.assertTrue(val0 > val1,
-                                "%s > %s" % (val0, val1))
+                self.assertGreater(val0, val1, "%s > %s" % (val0, val1))
 
         _list_details_with_multiple_params()
         _list_details_with_multiple_params(sort_dir='desc')
diff --git a/tempest/scenario/manager.py b/tempest/scenario/manager.py
index 48ed89c..9770f20 100644
--- a/tempest/scenario/manager.py
+++ b/tempest/scenario/manager.py
@@ -1018,7 +1018,7 @@
             if sg['tenant_id'] == tenant_id and sg['name'] == 'default'
         ]
         msg = "No default security group for tenant %s." % (tenant_id)
-        self.assertTrue(len(sgs) > 0, msg)
+        self.assertGreater(len(sgs), 0, msg)
         return sgs[0]
 
     def _create_security_group_rule(self, secgroup=None,
diff --git a/tempest/test.py b/tempest/test.py
index b75ae48..93fbed3 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -610,10 +610,10 @@
             cred_provider, networks_client, CONF.compute.fixed_network_name)
 
     def assertEmpty(self, list, msg=None):
-        self.assertTrue(len(list) == 0, msg)
+        self.assertEqual(0, len(list), msg)
 
     def assertNotEmpty(self, list, msg=None):
-        self.assertTrue(len(list) > 0, msg)
+        self.assertGreater(len(list), 0, msg)
 
 
 call_until_true = debtcollector.moves.moved_function(
diff --git a/tempest/tests/common/test_waiters.py b/tempest/tests/common/test_waiters.py
index b113c04..46f9526 100644
--- a/tempest/tests/common/test_waiters.py
+++ b/tempest/tests/common/test_waiters.py
@@ -37,7 +37,7 @@
         waiters.wait_for_image_status(self.client, 'fake_image_id', 'active')
         end_time = int(time.time())
         # Ensure waiter returns before build_timeout
-        self.assertTrue((end_time - start_time) < 10)
+        self.assertLess((end_time - start_time), 10)
 
     def test_wait_for_image_status_timeout(self):
         time_mock = self.patch('time.time')