Add hacking checks

There have been a handful of changes recently to fix stylistic bugs
in the unit tests (example: If41a7). The changes themselves were fine,
but there are two problems:

1) The stylistic changes they made were not listed in HACKING.rst
2) They were one-time changes; the rules that were violated will
   continue to be violated.

This change updates HACKING.rst to include a few of the stylistic
rules that have been fixed recently, and adds checks to ensure that
they will be enforced going forward. This is based on nova's hacking
checks.

Change-Id: Ic115342605c472f3a5d255aa570ecb60175ca087

HACKING.rst

@@ -8,4 +8,10 @@ glance Style Commandments
 glance Specific Commandments
 --------------------------
 
+- [G316] Change assertTrue(isinstance(A, B)) by optimal assert like
+  assertIsInstance(A, B)
+- [G317] Change assertEqual(type(A), B) by optimal assert like
+  assertIsInstance(A, B)
+- [G318] Change assertEqual(A, None) or assertEqual(None, A) by optimal assert like
+  assertIsNone(A)
 - [G319] Validate that debug level logs are not translated

glance/hacking/checks.py

@@ -12,6 +12,65 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import re
+
+"""
+Guidelines for writing new hacking checks
+
+ - Use only for Glance-specific tests. OpenStack general tests
+   should be submitted to the common 'hacking' module.
+ - Pick numbers in the range G3xx. Find the current test with
+   the highest allocated number and then pick the next value.
+   If nova has an N3xx code for that test, use the same number.
+ - Keep the test method code in the source file ordered based
+   on the G3xx value.
+ - List the new rule in the top level HACKING.rst file
+ - Add test cases for each new rule to glance/tests/test_hacking.py
+
+"""
+
+
+asse_trueinst_re = re.compile(
+    r"(.)*assertTrue\(isinstance\((\w|\.|\'|\"|\[|\])+, "
+    "(\w|\.|\'|\"|\[|\])+\)\)")
+asse_equal_type_re = re.compile(
+    r"(.)*assertEqual\(type\((\w|\.|\'|\"|\[|\])+\), "
+    "(\w|\.|\'|\"|\[|\])+\)")
+asse_equal_end_with_none_re = re.compile(
+    r"(.)*assertEqual\((\w|\.|\'|\"|\[|\])+, None\)")
+asse_equal_start_with_none_re = re.compile(
+    r"(.)*assertEqual\(None, (\w|\.|\'|\"|\[|\])+\)")
+
+
+def assert_true_instance(logical_line):
+    """Check for assertTrue(isinstance(a, b)) sentences
+
+    G316
+    """
+    if asse_trueinst_re.match(logical_line):
+        yield (0, "G316: assertTrue(isinstance(a, b)) sentences not allowed")
+
+
+def assert_equal_type(logical_line):
+    """Check for assertEqual(type(A), B) sentences
+
+    G317
+    """
+    if asse_equal_type_re.match(logical_line):
+        yield (0, "G317: assertEqual(type(A), B) sentences not allowed")
+
+
+def assert_equal_none(logical_line):
+    """Check for assertEqual(A, None) or assertEqual(None, A) sentences
+
+    G318
+    """
+    res = (asse_equal_start_with_none_re.match(logical_line) or
+           asse_equal_end_with_none_re.match(logical_line))
+    if res:
+        yield (0, "G318: assertEqual(A, None) or assertEqual(None, A) "
+               "sentences not allowed")
+
 
 def no_translate_debug_logs(logical_line, filename):
     dirs = [
@@ -33,4 +92,7 @@ def no_translate_debug_logs(logical_line, filename):
 
 
 def factory(register):
+    register(assert_true_instance)
+    register(assert_equal_type)
+    register(assert_equal_none)
     register(no_translate_debug_logs)

glance/tests/test_hacking.py

@@ -0,0 +1,43 @@
+#    Copyright 2014 IBM Corp.
+#
+#    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.
+
+from glance.hacking import checks
+from glance.tests import utils
+
+
+class HackingTestCase(utils.BaseTestCase):
+    def test_assert_true_instance(self):
+        self.assertEqual(1, len(list(checks.assert_true_instance(
+            "self.assertTrue(isinstance(e, "
+            "exception.BuildAbortException))"))))
+
+        self.assertEqual(
+            0, len(list(checks.assert_true_instance("self.assertTrue()"))))
+
+    def test_assert_equal_type(self):
+        self.assertEqual(1, len(list(checks.assert_equal_type(
+            "self.assertEqual(type(als['QuicAssist']), list)"))))
+
+        self.assertEqual(
+            0, len(list(checks.assert_equal_type("self.assertTrue()"))))
+
+    def test_assert_equal_none(self):
+        self.assertEqual(1, len(list(checks.assert_equal_none(
+            "self.assertEqual(A, None)"))))
+
+        self.assertEqual(1, len(list(checks.assert_equal_none(
+            "self.assertEqual(None, A)"))))
+
+        self.assertEqual(
+            0, len(list(checks.assert_equal_none("self.assertIsNone()"))))