Fixes #248

stix2/base.py

@@ -143,12 +143,12 @@ class _STIXBase(collections.Mapping):
         if custom_props:
             self.__allow_custom = True
 
-        # Remove any keyword arguments whose value is None
+        # Remove any keyword arguments whose value is None or [] (i.e. empty list)
         setting_kwargs = {}
         props = kwargs.copy()
         props.update(custom_props)
         for prop_name, prop_value in props.items():
-            if prop_value is not None:
+            if prop_value is not None and prop_value != []:
                 setting_kwargs[prop_name] = prop_value
 
         # Detect any missing required properties

stix2/test/v20/test_object_markings.py

@@ -107,7 +107,6 @@ def test_add_markings_combination():
     "data", [
         ([""]),
         (""),
-        ([]),
         ([MARKING_IDS[0], 456]),
     ],
 )
@@ -576,7 +575,6 @@ def test_set_marking():
 
 @pytest.mark.parametrize(
     "data", [
-        ([]),
         ([""]),
         (""),
         ([MARKING_IDS[4], 687]),

stix2/test/v21/test_object_markings.py

@@ -106,7 +106,6 @@ def test_add_markings_combination():
     "data", [
         ([""]),
         (""),
-        ([]),
         ([MARKING_IDS[0], 456]),
     ],
 )
@@ -575,7 +574,6 @@ def test_set_marking():
 
 @pytest.mark.parametrize(
     "data", [
-        ([]),
         ([""]),
         (""),
         ([MARKING_IDS[4], 687]),