Add "is not" test to hacking.py

HACKING.rst was updated in I7534ef73e6fd525fd8f4bee594a4b37524699c08.
This adds hacking.py enforcement.

Change-Id: I5d75d536762449d0a7ae38213addd02aeceede0b

1 files changed, 17 insertions, 3 deletions

diff --git a/tools/hacking.py b/tools/hacking.py
index 42a644e7d..d75595cc2 100755
--- a/tools/hacking.py
+++ b/tools/hacking.py
@@ -495,20 +495,34 @@ def nova_localization_strings(logical_line, tokens):
 #TODO(jogo) Dict and list objects
 
 
+def nova_is_not(logical_line):
+    r"""Check localization in line.
+
+    Okay: if x is not y
+    N901: if not X is Y
+    N901: if not X.B is Y
+    """
+    split_line = logical_line.split()
+    if (len(split_line) == 5 and split_line[0] == 'if' and
+            split_line[1] == 'not' and split_line[3] == 'is'):
+                yield (logical_line.find('not'), "N901: Use the 'is not' "
+                        "operator for when testing for unequal identities")
+
+
 def nova_not_in(logical_line):
     r"""Check localization in line.
 
     Okay: if x not in y
     Okay: if not (X in Y or X is Z)
     Okay: if not (X in Y)
-    N901: if not X in Y
-    N901: if not X.B in Y
+    N902: if not X in Y
+    N902: if not X.B in Y
     """
     split_line = logical_line.split()
     if (len(split_line) == 5 and split_line[0] == 'if' and
             split_line[1] == 'not' and split_line[3] == 'in' and not
             split_line[2].startswith('(')):
-                yield (logical_line.find('not'), "N901: Use the 'not in' "
+                yield (logical_line.find('not'), "N902: Use the 'not in' "
                         "operator for collection membership evaluation")
 
 current_file = ""