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/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)