Merge "Adding dict.items() concatenate validation"

tests/hacking/README.rst

@@ -30,4 +30,5 @@ Rally Specific Commandments
  * [N335] - Ensure that ``xrange`` is not used
  * [N336] - Ensure that ``string.lowercase`` and ``string.uppercase`` are not used
  * [N337] - Ensure that ``next()`` method on iterator objects is not used
+ * [N338] - Ensure that ``+`` operand is not used to concatenate dict.items()
 * [N340] - Ensure that we are importing always ``from rally import objects``

tests/hacking/checks.py

@@ -53,6 +53,8 @@ re_xrange_method = re.compile(r"(^|[\s=])xrange\(")
 re_string_lower_upper_case_method = re.compile(
     r"(^|[(,\s=])string\.(lower|upper)case([)\[,\s]|$)")
 re_next_on_iterator_method = re.compile(r"\.next\(\)")
+re_concatenate_dict = re.compile(
+    r".*\.items\(\)(\s*\+\s*.*\.items\(\))+.*")
 
 
 def _parse_assert_mock_str(line):
@@ -345,6 +347,21 @@ def check_next_on_iterator_method(logical_line):
         yield (0, "N337: Use next(iterator) rather than iterator.next().")
 
 
+def check_concatenate_dict_with_plus_operand(logical_line):
+    """Check if a dict is being sum with + operator
+
+    Python 3 dict.items() return a dict_items object instead of a list, and
+    this object, doesn't support + operator. Need to use the update method
+    instead in order to concatenate two dictionaries.
+
+    N338
+    """
+    res = re_concatenate_dict.search(logical_line)
+    if res:
+        yield (0, "N338: Use update() method instead of '+'' operand to "
+                  "concatenate dictionaries")
+
+
 def check_no_direct_rally_objects_import(logical_line, filename):
     """Check if rally.objects are properly imported.
 
@@ -381,3 +398,4 @@ def factory(register):
     register(check_string_lower_upper_case_method)
     register(check_next_on_iterator_method)
     register(check_no_direct_rally_objects_import)
+    register(check_concatenate_dict_with_plus_operand)

tests/unit/test_hacking.py

@@ -128,6 +128,33 @@ class HackingTestCase(test.TestCase):
         self.assertEqual(len(list(checks.check_iteritems_method(
             "dict.items()"))), 0)
 
+    def test_check_concatenate_dict_with_plus_operand(self):
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "dict1.items() + dict2.items()"))), 1)
+
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "dict(self.endpoint.to_dict().items() + "
+                "endpoint.items())"))), 1)
+
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "dict(self.endpoint.to_dict().items() + "
+                "endpoint.items() + something.items())"))), 1)
+
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "dict1.item() + dict2.item()"))), 0)
+
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "obj.getitems() + obj.getitems()"))), 0)
+
+        self.assertEqual(len(list(
+            checks.check_concatenate_dict_with_plus_operand(
+                "obj.getitems() + dict2.items()"))), 0)
+
     def test_check_basestring_method(self):
         self.assertEqual(len(list(checks.check_basestring_method(
             "basestring"))), 1)