Data structs declared with constructor replaced with literal

Changes:
  - list() declarations replaced with []
  - dict() declarations replaced with {}
  - Added N351 to hacking for literal rule along with checks, test hacking, and to readme
  - Minor fix to incorrect path in hacking guidelines pointing to test_hacking.py

Change-Id: Ie7b9201d61b6f2024217b6f4117605eb52fa916a
Closes-Bug: #1437515

tests/functional/test_cli_task.py

@@ -143,7 +143,7 @@ class TaskTestCase(unittest.TestCase):
         rally = utils.Rally()
         cfg = self._get_sample_task_config()
         config = utils.TaskConfig(cfg)
-        task_uuids = list()
+        task_uuids = []
         for i in range(3):
             res = rally("task start --task %s" % config.filename)
             for line in res.splitlines():
@@ -158,7 +158,7 @@ class TaskTestCase(unittest.TestCase):
         rally = utils.Rally()
         cfg = self._get_sample_task_config()
         config = utils.TaskConfig(cfg)
-        files = list()
+        files = []
         for i in range(3):
             rally("task start --task %s" % config.filename)
             path = "/tmp/task_%d.json" % i
@@ -241,7 +241,7 @@ class TaskTestCase(unittest.TestCase):
 
         # Validate against a single task
         res = rally("task start --task %s" % config.filename)
-        task_uuids = list()
+        task_uuids = []
         for line in res.splitlines():
             if "finished" in line:
                 task_uuids.append(line.split(" ")[1][:-1])

tests/functional/utils.py

@@ -97,7 +97,7 @@ class Rally(object):
 
         self.reports_root = os.environ.get("REPORTS_ROOT",
                                            "rally-cli-output-files")
-        self._created_files = list()
+        self._created_files = []
 
         self("deployment create --file %s --name MAIN" % DEPLOYMENT_FILE,
              write_report=False)

tests/hacking/README.rst

@@ -24,3 +24,4 @@ Rally Specific Commandments
 * [N340] - Ensure that we are importing always ``from rally import objects``
 * [N341] - Ensure that we are importing oslo_xyz packages instead of deprecated oslo.xyz ones
 * [N350] - Ensure that single quotes are not used
+* [N351] - Ensure that data structs (i.e Lists and Dicts) are declared literally rather than using constructors

tests/hacking/checks.py

@@ -20,7 +20,7 @@ Guidelines for writing new hacking checks
  - Keep the test method code in the source file ordered based
    on the N3xx value.
  - List the new rule in the top level HACKING.rst file
- - Add test cases for each new rule to tests/test_hacking.py
+ - Add test cases for each new rule to tests/unit/test_hacking.py
 
 """
 
@@ -46,6 +46,10 @@ re_assert_equal_in_end_with_true_or_false = re.compile(
     r"assertEqual\((\w|[][.'\"])+( not)? in (\w|[][.'\", ])+, (True|False)\)")
 re_assert_equal_in_start_with_true_or_false = re.compile(
     r"assertEqual\((True|False), (\w|[][.'\"])+( not)? in (\w|[][.'\", ])+\)")
+re_no_construct_dict = re.compile(
+    r"=\sdict\(\)")
+re_no_construct_list = re.compile(
+    r"=\slist\(\)")
 
 
 def skip_ignored_lines(func):
@@ -333,6 +337,21 @@ def check_quotes(logical_line, filename):
         yield (i, "N350 Remove Single quotes")
 
 
+@skip_ignored_lines
+def check_no_constructor_data_struct(logical_line, filename):
+    """Check that data structs (lists, dicts) are declared using literals
+
+    N351
+    """
+
+    match = re_no_construct_dict.search(logical_line)
+    if match:
+        yield (0, "N351 Remove dict() construct and use literal {}")
+    match = re_no_construct_list.search(logical_line)
+    if match:
+        yield (0, "N351 Remove list() construct and use literal []")
+
+
 def factory(register):
     register(check_assert_methods_from_mock)
     register(check_import_of_logging)
@@ -346,3 +365,4 @@ def factory(register):
     register(check_no_direct_rally_objects_import)
     register(check_no_oslo_deprecated_import)
     register(check_quotes)
+    register(check_no_constructor_data_struct)

tests/unit/test_hacking.py

@@ -245,3 +245,18 @@ class HackingTestCase(test.TestCase):
             "a = ''   # noqa "
         ]
         self._assert_good_samples(checks.check_quotes, good_lines)
+
+    def test_check_no_constructor_data_struct(self):
+        bad_struct = [
+            "= dict()",
+            "= list()"
+        ]
+        self._assert_bad_samples(checks.check_no_constructor_data_struct,
+                                 bad_struct)
+
+        good_struct = [
+            "= []",
+            "= {}",
+        ]
+        self._assert_good_samples(checks.check_no_constructor_data_struct,
+                                  good_struct)