test: fix default value for additional param

In Python, the default values of parameters are evaluated only once
during their declaration. So, whenever the default parameter is used
the same object will be used. Since we use a list, which is a mutable
object, this could lead to unexpected results.

PR-URL: https://github.com/nodejs/node/pull/2553
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/testpy/__init__.py

@@ -40,14 +40,17 @@ FILES_PATTERN = re.compile(r"//\s+Files:(.*)")
 
 class SimpleTestCase(test.TestCase):
 
-  def __init__(self, path, file, arch, mode, context, config, additional=[]):
+  def __init__(self, path, file, arch, mode, context, config, additional=None):
     super(SimpleTestCase, self).__init__(context, path, arch, mode)
     self.file = file
     self.config = config
     self.arch = arch
     self.mode = mode
     self.tmpdir = join(dirname(self.config.root), 'tmp')
+    if additional is not None:
       self.additional_flags = additional
+    else:
+      self.additional_flags = []
 
 
   def GetLabel(self):
@@ -81,10 +84,13 @@ class SimpleTestCase(test.TestCase):
 
 class SimpleTestConfiguration(test.TestConfiguration):
 
-  def __init__(self, context, root, section, additional=[]):
+  def __init__(self, context, root, section, additional=None):
     super(SimpleTestConfiguration, self).__init__(context, root)
     self.section = section
+    if additional is not None:
       self.additional_flags = additional
+    else:
+      self.additional_flags = []
 
   def Ls(self, path):
     def SelectTest(name):
@@ -110,7 +116,7 @@ class SimpleTestConfiguration(test.TestConfiguration):
       test.ReadConfigurationInto(status_file, sections, defs)
 
 class ParallelTestConfiguration(SimpleTestConfiguration):
-  def __init__(self, context, root, section, additional=[]):
+  def __init__(self, context, root, section, additional=None):
     super(ParallelTestConfiguration, self).__init__(context, root, section,
                                                     additional)
 
@@ -122,8 +128,8 @@ class ParallelTestConfiguration(SimpleTestConfiguration):
     return result
 
 class AddonTestConfiguration(SimpleTestConfiguration):
-  def __init__(self, context, root, section, additional=[]):
+  def __init__(self, context, root, section, additional=None):
-    super(AddonTestConfiguration, self).__init__(context, root, section)
+    super(AddonTestConfiguration, self).__init__(context, root, section, additional)
 
   def Ls(self, path):
     def SelectTest(name):