Adds initial hacking checks to Patrole

This patch:
  - Adds hacking check to Patrole (executed via tox -e pep8)
  - Corrects a few hacking errors
  - Adds hacking documentation to Patrole

Change-Id: Id43e24060a5290df91c594df6a38ba0cb239bbaf
diff --git a/HACKING.rst b/HACKING.rst
index bb337b0..b1d730d 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -1,6 +1,62 @@
 Patrole Style Commandments
 ==========================
 
-Read the OpenStack Style Commandments: `<http://docs.openstack.org/developer/hacking/>`__
+- Step 1: Read the OpenStack Style Commandments: `<http://docs.openstack.org/developer/hacking/>`__
+- Step 2: Review Tempest's Style Commandments: `<https://docs.openstack.org/developer/tempest/HACKING.html>`__
+- Step 3: Read on
 
-Also review Tempest's Style Commandments: `<https://docs.openstack.org/developer/tempest/HACKING.html>`__
+Patrole Specific Commandments
+------------------------------
+
+Patrole borrows the following commandments from Tempest; refer to
+`Tempest's Commandments <https://docs.openstack.org/developer/tempest/HACKING.html>`__
+for more information:
+
+.. note::
+
+    The original Tempest Commandments do not include Patrole-specific paths.
+    Patrole-specific paths replace the Tempest-specific paths within Patrole's
+    hacking checks.
+..
+
+- [T102] Cannot import OpenStack python clients in patrole_tempest_plugin/tests/api
+- [T105] Tests cannot use setUpClass/tearDownClass
+- [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
+- [T113] Check that tests use data_utils.rand_uuid() instead of uuid.uuid4()
+- [N322] Method's default argument shouldn't be mutable
+
+The following are Patrole's specific Commandments:
+
+- [P100] The ``rbac_rule_validation.action`` decorator must be applied to
+         an RBAC test (the check fails if the decorator is not one of the
+         two decorators directly above the function declaration)
+- [P101] RBAC test filenames must end with "_rbac.py"; for example,
+         test_servers_rbac.py, not test_servers.py
+- [P102] RBAC test class names must end in 'RbacTest'
+
+Role Switching
+--------------
+
+Correct role switching is vital to correct RBAC testing within Patrole. If a
+test does not call ``rbac_utils.switch_role`` with ``toggle_rbac_role=True``
+within the RBAC test, then the test is *not* a valid RBAC test: The API
+endpoint under test will be performed with admin credentials, which is always
+wrong unless ``CONF.rbac_test_role`` is admin.
+
+.. note::
+
+    Switching back to the admin role for setup and clean up is automatically
+    performed. Toggling ``switch_role`` with ``toggle_rbac_role=False`` within
+    the context of a test should *never* be performed and doing so will likely
+    result in an error being thrown.
+..
+
+Patrole does not have a hacking check for role switching, but does use a
+built-in mechanism for verifying that role switching is being correctly
+executed across tests. If a test does not call ``switch_role`` with
+``toggle_rbac_role=True``, then an ``RbacResourceSetupFailed`` exception
+will be raised.
diff --git a/patrole_tempest_plugin/hacking/__init__.py b/patrole_tempest_plugin/hacking/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/patrole_tempest_plugin/hacking/__init__.py
diff --git a/patrole_tempest_plugin/hacking/checks.py b/patrole_tempest_plugin/hacking/checks.py
new file mode 100644
index 0000000..e7e5cb0
--- /dev/null
+++ b/patrole_tempest_plugin/hacking/checks.py
@@ -0,0 +1,216 @@
+# Copyright 2013 IBM Corp.
+# Copyright 2017 AT&T Corporation.
+# All Rights Reserved.
+#
+#   Licensed under the Apache License, Version 2.0 (the "License"); you may
+#   not use this file except in compliance with the License. You may obtain
+#   a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#   WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#   License for the specific language governing permissions and limitations
+#   under the License.
+
+import os
+import re
+
+import pep8
+
+
+PYTHON_CLIENTS = ['cinder', 'glance', 'keystone', 'nova', 'swift', 'neutron',
+                  'ironic', 'heat', 'sahara']
+
+PYTHON_CLIENT_RE = re.compile('import (%s)client' % '|'.join(PYTHON_CLIENTS))
+TEST_DEFINITION = re.compile(r'^\s*def test.*')
+SETUP_TEARDOWN_CLASS_DEFINITION = re.compile(r'^\s+def (setUp|tearDown)Class')
+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\((.*)\)')
+TEST_METHOD = re.compile(r"^    def test_.+")
+CLASS = re.compile(r"^class .+")
+RBAC_CLASS_NAME_RE = re.compile(r'class .+RbacTest')
+RULE_VALIDATION_DECORATOR = re.compile(
+    r'\s*@.*rbac_rule_validation.action\((.*)\)')
+IDEMPOTENT_ID_DECORATOR = re.compile(r'\s*@decorators\.idempotent_id\((.*)\)')
+
+previous_decorator = None
+
+
+def import_no_clients_in_api_tests(physical_line, filename):
+    """Check for client imports from patrole_tempest_plugin/tests/api
+
+    T102: Cannot import OpenStack python clients
+    """
+    if "patrole_tempest_plugin/tests/api" in filename:
+        res = PYTHON_CLIENT_RE.match(physical_line)
+        if res:
+            return (physical_line.find(res.group(1)),
+                    ("T102: python clients import not allowed "
+                     "in patrole_tempest_plugin/tests/api/* or "
+                     "patrole_tempest_plugin/tests/scenario/* tests"))
+
+
+def no_setup_teardown_class_for_tests(physical_line, filename):
+    """Check that tests do not use setUpClass/tearDownClass
+
+    T105: Tests cannot use setUpClass/tearDownClass
+    """
+    if pep8.noqa(physical_line):
+        return
+
+    if SETUP_TEARDOWN_CLASS_DEFINITION.match(physical_line):
+        return (physical_line.find('def'),
+                "T105: (setUp|tearDown)Class can not be used in tests")
+
+
+def no_vi_headers(physical_line, line_number, lines):
+    """Check for vi editor configuration in source files.
+
+    By default vi modelines can only appear in the first or
+    last 5 lines of a source file.
+
+    T106
+    """
+    # NOTE(gilliard): line_number is 1-indexed
+    if line_number <= 5 or line_number > len(lines) - 5:
+        if VI_HEADER_RE.match(physical_line):
+            return 0, "T106: Don't put vi configuration in source files"
+
+
+def service_tags_not_in_module_path(physical_line, filename):
+    """Check that a service tag isn't in the module path
+
+    A service tag should only be added if the service name isn't already in
+    the module path.
+
+    T107
+    """
+    matches = SCENARIO_DECORATOR.match(physical_line)
+    if matches:
+        services = matches.group(1).split(',')
+        for service in services:
+            service_name = service.strip().strip("'")
+            modulepath = os.path.split(filename)[0]
+            if service_name in modulepath:
+                return (physical_line.find(service_name),
+                        "T107: service tag should not be in path")
+
+
+def no_hyphen_at_end_of_rand_name(logical_line, filename):
+    """Check no hyphen at the end of rand_name() argument
+
+    T108
+    """
+    msg = "T108: hyphen should not be specified at the end of rand_name()"
+    if RAND_NAME_HYPHEN_RE.match(logical_line):
+        return 0, msg
+
+
+def no_mutable_default_args(logical_line):
+    """Check that mutable object isn't used as default argument
+
+    N322: Method's default argument shouldn't be mutable
+    """
+    msg = "N322: Method's default argument shouldn't be mutable!"
+    if MUTABLE_DEFAULT_ARGS.match(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 use_rand_uuid_instead_of_uuid4(logical_line, filename):
+    """Check that tests use data_utils.rand_uuid() instead of uuid.uuid4()
+
+    T113
+    """
+    if 'uuid.uuid4()' not in logical_line:
+        return
+
+    msg = ("T113: Tests should use data_utils.rand_uuid()/rand_uuid_hex() "
+           "instead of uuid.uuid4()/uuid.uuid4().hex")
+    yield (0, msg)
+
+
+def no_rbac_rule_validation_decorator(physical_line, filename,
+                                      previous_logical):
+    """Check that each test has the ``rbac_rule_validation.action`` decorator.
+
+    Checks whether the test function has "@rbac_rule_validation.action"
+    above it; otherwise checks that it has "@decorators.idempotent_id" above
+    it and "@rbac_rule_validation.action" above that.
+
+    Assumes that ``rbac_rule_validation.action`` decorator is either the first
+    or second decorator above the test function; otherwise this check fails.
+
+    P100
+    """
+    global previous_decorator
+
+    if "patrole_tempest_plugin/tests/api" in filename:
+
+        if IDEMPOTENT_ID_DECORATOR.match(physical_line):
+            previous_decorator = previous_logical
+            return
+
+        if TEST_METHOD.match(physical_line):
+            if not RULE_VALIDATION_DECORATOR.match(previous_logical) and \
+                not RULE_VALIDATION_DECORATOR.match(previous_decorator):
+                    return (0, "Must use rbac_rule_validation.action "
+                               "decorator for API and scenario tests")
+
+
+def no_rbac_suffix_in_test_filename(physical_line, filename, previous_logical):
+    """Check that RBAC filenames end with "_rbac" suffix.
+
+    P101
+    """
+    if "patrole_tempest_plugin/tests/api" in filename:
+
+        if filename.endswith('rbac_base.py'):
+            return
+
+        if not filename.endswith('_rbac.py'):
+            return 0, "RBAC test filenames must end in _rbac suffix"
+
+
+def no_rbac_test_suffix_in_test_class_name(physical_line, filename,
+                                           previous_logical):
+    """Check that RBAC class names end with "RbacTest"
+
+    P102
+    """
+    if "patrole_tempest_plugin/tests/api" in filename:
+
+        if filename.endswith('rbac_base.py'):
+            return
+
+        if CLASS.match(physical_line):
+            if not RBAC_CLASS_NAME_RE.match(physical_line):
+                return 0, "RBAC test class names must end in 'RbacTest'"
+
+
+def factory(register):
+    register(import_no_clients_in_api_tests)
+    register(no_setup_teardown_class_for_tests)
+    register(no_vi_headers)
+    register(no_hyphen_at_end_of_rand_name)
+    register(no_mutable_default_args)
+    register(no_testtools_skip_decorator)
+    register(use_rand_uuid_instead_of_uuid4)
+    register(service_tags_not_in_module_path)
+    register(no_rbac_rule_validation_decorator)
+    register(no_rbac_suffix_in_test_filename)
+    register(no_rbac_test_suffix_in_test_class_name)
diff --git a/patrole_tempest_plugin/rbac_policy_parser.py b/patrole_tempest_plugin/rbac_policy_parser.py
index 8256889..d4e989b 100644
--- a/patrole_tempest_plugin/rbac_policy_parser.py
+++ b/patrole_tempest_plugin/rbac_policy_parser.py
@@ -40,8 +40,7 @@
     each role, whether a given rule is allowed using oslo policy.
     """
 
-    def __init__(self, project_id, user_id, service=None,
-                 extra_target_data={}):
+    def __init__(self, project_id, user_id, service, extra_target_data=None):
         """Initialization of Rbac Policy Parser.
 
         Parses a policy file to create a dictionary, mapping policy actions to
@@ -64,6 +63,9 @@
         :param path: type string
         """
 
+        if extra_target_data is None:
+            extra_target_data = {}
+
         # First check if the service is valid
         service = service.lower().strip() if service else None
         self.admin_mgr = credentials.AdminManager()
diff --git a/patrole_tempest_plugin/rbac_rule_validation.py b/patrole_tempest_plugin/rbac_rule_validation.py
index 8de3d97..d77b2d6 100644
--- a/patrole_tempest_plugin/rbac_rule_validation.py
+++ b/patrole_tempest_plugin/rbac_rule_validation.py
@@ -31,7 +31,7 @@
 
 
 def action(service, rule='', admin_only=False, expected_error_code=403,
-           extra_target_data={}):
+           extra_target_data=None):
     """A decorator which does a policy check and matches it against test run.
 
     A decorator which allows for positive and negative RBAC testing. Given
@@ -62,6 +62,10 @@
     :raises Forbidden: for bullet (2) above.
     :raises RbacOverPermission: for bullet (3) above.
     """
+
+    if extra_target_data is None:
+        extra_target_data = {}
+
     def decorator(func):
         role = CONF.rbac.rbac_test_role
 
diff --git a/requirements.txt b/requirements.txt
index ffc6abe..6d2c7f1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-
+hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 pbr>=1.8 # Apache-2.0
 urllib3>=1.15.1 # MIT
 oslo.log>=3.11.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index a004c6e..be35509 100644
--- a/tox.ini
+++ b/tox.ini
@@ -59,3 +59,6 @@
 ignore = E123,E125
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
+
+[hacking]
+local-check-factory = patrole_tempest_plugin.hacking.checks.factory