fix lint-py issues

Author: vmoroz

test/testpy/__init__.py

@@ -178,9 +178,9 @@ def Ls(self, path):
         result.append([subpath, 'run-tests'])
         continue
 
-      for name in files:
-        if name.endswith('.js'):
-          result.append([subpath, name[:-3]])
+      result.extend([ [subpath, name[:-3]]
+                      for name in files
+                      if name.endswith('.js') ])
 
     return result