[core][wmi] list to cache connections

Use a `list` to cache WMI connections instead of a `set`.

checks/libs/wmi/sampler.py

@@ -53,7 +53,7 @@ class WMISampler(object):
     """
     # Shared resources
     _wmi_locators = {}
-    _wmi_connections = defaultdict(set)
+    _wmi_connections = defaultdict(list)
 
     def __init__(self, logger, class_name, property_names, filters="", host="localhost",
                  namespace="root\\cimv2", username="", password="", timeout_duration=10):
@@ -293,7 +293,7 @@ def get_connection(self):
         yield connection
 
         # Release it
-        self._wmi_connections[self.connection_key].add(connection)
+        self._wmi_connections[self.connection_key].append(connection)
 
     @staticmethod
     def _format_filter(filters):

tests/core/test_wmi.py

@@ -224,7 +224,7 @@ def tearDown(self):
         # Flush cache
         from checks.libs.wmi.sampler import WMISampler
         WMISampler._wmi_locators = {}
-        WMISampler._wmi_connections = defaultdict(set)
+        WMISampler._wmi_connections = defaultdict(list)
 
     def assertWMIConn(self, wmi_sampler, param=None, count=None):
         """

tests/core/test_wmi_calculator.py

@@ -36,7 +36,7 @@ def test_calculator_decorator(self):
         Asssign a calculator to a counter_type. Raise when the calculator is missing.
         """
         @calculator(123456)
-        def do_something():
+        def do_something(*args, **kwargs):
             """A function that does something."""
             pass