Fixes 'not in' operator usage

Change-Id: I1e26a8fcb9fa564308e63c11a72aaa55119e4eee

HACKING.rst

@@ -29,6 +29,18 @@ General
     mylist = Foo().list() # OKAY, does not shadow built-in
 
 
+- Use the "not in" operator for collection membership evaluation. Example::
+
+    if not X in Y:  # BAD, hard to understand
+        pass
+
+    if X not in Y:  # OKAY, intuitive
+        pass
+
+    if not (X in Y or X is Z):  # OKAY, still better than all those 'not's
+        pass
+
+
 Imports
 -------
 - Do not import objects, only modules (*)

nova/tests/test_libvirt.py

@@ -3848,7 +3848,7 @@ class IptablesFirewallTestCase(test.TestCase):
         in_rules = filter(lambda l: not l.startswith('#'),
                           self.in_rules)
         for rule in in_rules:
-            if not 'nova' in rule:
+            if 'nova' not in rule:
                 self.assertTrue(rule in self.out_rules,
                                 'Rule went missing: %s' % rule)
 

nova/tests/test_virt_disk_vfs_localfs.py

@@ -46,7 +46,7 @@ def fake_execute(*args, **kwargs):
     elif args[0] == "chown":
         owner = args[1]
         path = args[2]
-        if not path in files:
+        if path not in files:
             raise Exception("No such file: " + path)
 
         sep = owner.find(':')
@@ -72,7 +72,7 @@ def fake_execute(*args, **kwargs):
     elif args[0] == "chgrp":
         group = args[1]
         path = args[2]
-        if not path in files:
+        if path not in files:
             raise Exception("No such file: " + path)
 
         if group == "users":
@@ -83,13 +83,13 @@ def fake_execute(*args, **kwargs):
     elif args[0] == "chmod":
         mode = args[1]
         path = args[2]
-        if not path in files:
+        if path not in files:
             raise Exception("No such file: " + path)
 
         files[path]["mode"] = int(mode, 8)
     elif args[0] == "cat":
         path = args[1]
-        if not path in files:
+        if path not in files:
             files[path] = {
                 "content": "Hello World",
                 "gid": 100,
@@ -104,7 +104,7 @@ def fake_execute(*args, **kwargs):
         else:
             path = args[1]
             append = False
-        if not path in files:
+        if path not in files:
             files[path] = {
                 "content": "Hello World",
                 "gid": 100,

nova/tests/test_xenapi.py

@@ -595,7 +595,7 @@ class XenAPIVMTestCase(stubs.XenAPITestBase):
 
     def _check_vdis(self, start_list, end_list):
         for vdi_ref in end_list:
-            if not vdi_ref in start_list:
+            if vdi_ref not in start_list:
                 vdi_rec = xenapi_fake.get_record('VDI', vdi_ref)
                 # If the cache is turned on then the base disk will be
                 # there even after the cleanup
@@ -1949,7 +1949,7 @@ class XenAPIDom0IptablesFirewallTestCase(stubs.XenAPITestBase):
         in_rules = filter(lambda l: not l.startswith('#'),
                           self._in_rules)
         for rule in in_rules:
-            if not 'nova' in rule:
+            if 'nova' not in rule:
                 self.assertTrue(rule in self._out_rules,
                                 'Rule went missing: %s' % rule)