Sahara: minor changes for API tests

* Code refactoring of "test_node_group_template_create" test
  (file test_node_group_templates.py) was done.
* Unnecessary blank lines were removed.

Partially implements: blueprint savanna-api-tests

Change-Id: Id21edafcc4d1d0345b72404a55bbf9d69618cd95
diff --git a/tempest/api/data_processing/test_node_group_templates.py b/tempest/api/data_processing/test_node_group_templates.py
index f3af4e8..04f98b4 100644
--- a/tempest/api/data_processing/test_node_group_templates.py
+++ b/tempest/api/data_processing/test_node_group_templates.py
@@ -46,7 +46,7 @@
         It creates template and ensures response status and template name.
         Returns id and name of created template.
         """
-        if template_name is None:
+        if not template_name:
             # generate random name if it's not specified
             template_name = data_utils.rand_name('sahara-ng-template')
 
@@ -57,19 +57,13 @@
         # ensure that template created successfully
         self.assertEqual(202, resp.status)
         self.assertEqual(template_name, body['name'])
+        self.assertDictContainsSubset(self.node_group_template, body)
 
         return body['id'], template_name
 
     @test.attr(type='smoke')
     def test_node_group_template_create(self):
-        template_name = data_utils.rand_name('sahara-ng-template')
-        resp, body = self.create_node_group_template(
-            template_name, **self.node_group_template)
-
-        # check that template created successfully
-        self.assertEqual(resp.status, 202)
-        self.assertEqual(template_name, body['name'])
-        self.assertDictContainsSubset(self.node_group_template, body)
+        self._create_node_group_template()
 
     @test.attr(type='smoke')
     def test_node_group_template_list(self):
@@ -77,7 +71,6 @@
 
         # check for node group template in list
         resp, templates = self.client.list_node_group_templates()
-
         self.assertEqual(200, resp.status)
         templates_info = [(template['id'], template['name'])
                           for template in templates]
@@ -89,7 +82,6 @@
 
         # check node group template fetch by id
         resp, template = self.client.get_node_group_template(template_id)
-
         self.assertEqual(200, resp.status)
         self.assertEqual(template_name, template['name'])
         self.assertDictContainsSubset(self.node_group_template, template)
@@ -100,5 +92,4 @@
 
         # delete the node group template by id
         resp = self.client.delete_node_group_template(template_id)[0]
-
         self.assertEqual(204, resp.status)
diff --git a/tempest/api/data_processing/test_plugins.py b/tempest/api/data_processing/test_plugins.py
index c6832a2..d643f23 100644
--- a/tempest/api/data_processing/test_plugins.py
+++ b/tempest/api/data_processing/test_plugins.py
@@ -23,10 +23,8 @@
         It ensures response status and main plugins availability.
         """
         resp, plugins = self.client.list_plugins()
-
         self.assertEqual(200, resp.status)
-
-        plugins_names = list([plugin['name'] for plugin in plugins])
+        plugins_names = [plugin['name'] for plugin in plugins]
         self.assertIn('vanilla', plugins_names)
         self.assertIn('hdp', plugins_names)
 
@@ -40,14 +38,12 @@
     def test_plugin_get(self):
         for plugin_name in self._list_all_plugin_names():
             resp, plugin = self.client.get_plugin(plugin_name)
-
             self.assertEqual(200, resp.status)
             self.assertEqual(plugin_name, plugin['name'])
 
             for plugin_version in plugin['versions']:
                 resp, detailed_plugin = self.client.get_plugin(plugin_name,
                                                                plugin_version)
-
                 self.assertEqual(200, resp.status)
                 self.assertEqual(plugin_name, detailed_plugin['name'])