Add hacking check for testtools.skip

Adding hacking check for testtools.skip decorator as described
in the bug referenced below.

Closes-Bug: #1490590
Change-Id: I9c456bb8b57a54fbcd1cd5249eec2292916d4ff9

HACKING.rst

@@ -15,6 +15,8 @@ Tempest Specific Commandments
 - [T106] vim configuration should not be kept in source files.
 - [T107] Check that a service tag isn't in the module path
 - [T108] Check no hyphen at the end of rand_name() argument
+- [T109] Cannot use testtools.skip decorator; instead use
+         decorators.skip_because from tempest-lib
 - [N322] Method's default argument shouldn't be mutable
 
 Test Data/Configuration

tempest/hacking/checks.py

@@ -29,6 +29,7 @@ SCENARIO_DECORATOR = re.compile(r'\s*@.*services\((.*)\)')
 VI_HEADER_RE = re.compile(r"^#\s+vim?:.+")
 RAND_NAME_HYPHEN_RE = re.compile(r".*rand_name\(.+[\-\_][\"\']\)")
 mutable_default_args = re.compile(r"^\s*def .+\((.+=\{\}|.+=\[\])")
+TESTTOOLS_SKIP_DECORATOR = re.compile(r'\s*@testtools\.skip\((.*)\)')
 
 
 def import_no_clients_in_api_and_scenario_tests(physical_line, filename):
@@ -132,6 +133,16 @@ def no_mutable_default_args(logical_line):
         yield (0, msg)
 
 
+def no_testtools_skip_decorator(logical_line):
+    """Check that methods do not have the testtools.skip decorator
+
+    T109
+    """
+    if TESTTOOLS_SKIP_DECORATOR.match(logical_line):
+        yield (0, "T109: Cannot use testtools.skip decorator; instead use "
+               "decorators.skip_because from tempest-lib")
+
+
 def factory(register):
     register(import_no_clients_in_api_and_scenario_tests)
     register(scenario_tests_need_service_tags)
@@ -140,3 +151,4 @@ def factory(register):
     register(service_tags_not_in_module_path)
     register(no_hyphen_at_end_of_rand_name)
     register(no_mutable_default_args)
+    register(no_testtools_skip_decorator)

tempest/tests/test_hacking.py

@@ -138,3 +138,11 @@ class HackingTestCase(base.TestCase):
 
         self.assertEqual(0, len(list(checks.no_mutable_default_args(
             "defined, undefined = [], {}"))))
+
+    def test_no_testtools_skip_decorator(self):
+        self.assertEqual(1, len(list(checks.no_testtools_skip_decorator(
+            " @testtools.skip('Bug xxx')"))))
+        self.assertEqual(0, len(list(checks.no_testtools_skip_decorator(
+            " @testtools.skipUnless(CONF.something, 'msg')"))))
+        self.assertEqual(0, len(list(checks.no_testtools_skip_decorator(
+            " @testtools.skipIf(CONF.something, 'msg')"))))