Use six.string_types instead of basestring

There is no global variable "basestring" in Python 3.
"six.string_types" should be used to support both Python 2 and Python 3

Change-Id: I556fef0e98d00ab819e3dea961666b403b927b06
Closes-bug:#1403077

tests/hacking/README.rst

@@ -23,3 +23,4 @@ Rally Specific Commandments
  * [N324] - Ensure that ``assertEqual(A in/not in B, True/False)`` and ``assertEqual(True/False, A in/not in B)`` are not used with collection contents
 * [N33x] - Reserved for rules related to Python 3 compatibility
  * [N330] - Ensure that ``dict.iteritems()`` is not used
+ * [N331] - Ensure that ``basestring`` is not used

tests/hacking/checks.py

@@ -46,6 +46,7 @@ re_assert_equal_in_end_with_true_or_false = re.compile(
 re_assert_equal_in_start_with_true_or_false = re.compile(
     r"assertEqual\((True|False), (\w|[][.'\"])+( not)? in (\w|[][.'\", ])+\)")
 re_iteritems_method = re.compile(r"\.iteritems\(\)")
+re_basestring_method = re.compile(r"(^|[\s,(\[=])basestring([\s,)\]]|$)")
 
 
 def _parse_assert_mock_str(line):
@@ -232,13 +233,25 @@ def check_iteritems_method(logical_line):
 
     N330
     """
-
     res = re_iteritems_method.search(logical_line)
     if res:
         yield (0, "N330: Use six.iteritems(dict) or dict.items() rather than "
                   "dict.iteritems() to iterate a collection.")
 
 
+def check_basestring_method(logical_line):
+    """Check if basestring is properly called for compatibility with Python 3
+
+    There is no global variable "basestring" in Python 3.The correct form
+    is six.string_types, instead of basestring.
+
+    N331
+    """
+    res = re_basestring_method.search(logical_line)
+    if res:
+        yield (0, "N331: Use six.string_types rather than basestring.")
+
+
 def factory(register):
     register(check_assert_methods_from_mock)
     register(check_import_of_logging)
@@ -250,3 +263,4 @@ def factory(register):
     register(assert_true_or_false_with_in)
     register(assert_equal_in)
     register(check_iteritems_method)
+    register(check_basestring_method)

tests/unit/fakes.py

@@ -344,7 +344,7 @@ class FakeServerManager(FakeManager):
         pass
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -383,7 +383,7 @@ class FakeImageManager(FakeManager):
         return self._create(name=name)
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -440,7 +440,7 @@ class FakeKeypairManager(FakeManager):
         return self._cache(kp)
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -458,7 +458,7 @@ class FakeStackManager(FakeManager):
         return self._cache(stack)
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -476,7 +476,7 @@ class FakeDomainManager(FakeManager):
         return self._cache(domain)
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -533,7 +533,7 @@ class FakeSecurityGroupManager(FakeManager):
         raise nova_exceptions.NotFound('Security Group not found')
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)
@@ -765,7 +765,7 @@ class FakeDbInstanceManager(FakeManager):
         return self.__db_instances.values()
 
     def delete(self, resource):
-        if not isinstance(resource, basestring):
+        if not isinstance(resource, six.string_types):
             resource = resource.id
 
         cached = self.get(resource)

tests/unit/test_hacking.py

@@ -128,6 +128,13 @@ class HackingTestCase(test.TestCase):
         self.assertEqual(len(list(checks.check_iteritems_method(
             "dict.items()"))), 0)
 
+    def test_check_basestring_method(self):
+        self.assertEqual(len(list(checks.check_basestring_method(
+            "basestring"))), 1)
+
+        self.assertEqual(len(list(checks.check_basestring_method(
+            "six.string_types"))), 0)
+
     def test_assert_equal_none(self):
         self.assertEqual(len(list(checks.assert_equal_none(
             "self.assertEqual(A, None)"))), 1)