Changed the abstract columns and datalists from test cases of common and Identity

columns and datalist has been set in each test case in compute,
which is not necessary. This patch abstract it out and remove
all redundant code.

Change-Id: I45a3582088161f12e60e7c933da8e7dcc0ae8e7b
Closes-Bug: #1532384

openstackclient/tests/common/test_timing.py

@@ -33,6 +33,11 @@ class FakeGenericClient(object):
 
 class TestTiming(utils.TestCommand):
 
+    columns = (
+        'URL',
+        'Seconds',
+    )
+
     def setUp(self):
         super(TestTiming, self).setUp()
 
@@ -59,8 +64,7 @@ class TestTiming(utils.TestCommand):
         # DisplayCommandBase.take_action() returns two tuples
         columns, data = self.cmd.take_action(parsed_args)
 
-        collist = ('URL', 'Seconds')
-        self.assertEqual(collist, columns)
+        self.assertEqual(self.columns, columns)
         datalist = [
             ('Total', 0.0,)
         ]
@@ -78,9 +82,7 @@ class TestTiming(utils.TestCommand):
 
         # DisplayCommandBase.take_action() returns two tuples
         columns, data = self.cmd.take_action(parsed_args)
-
-        collist = ('URL', 'Seconds')
-        self.assertEqual(collist, columns)
+        self.assertEqual(self.columns, columns)
         datalist = [
             (timing_url, timing_elapsed),
             ('Total', timing_elapsed),