Merge "command: make run() return take_action() value"

cliff/command.py

@@ -40,6 +40,8 @@ class Command(object):
     @abc.abstractmethod
     def take_action(self, parsed_args):
         """Override to do something useful.
+
+        The returned value will be returned by the program.
         """
 
     def run(self, parsed_args):
@@ -51,6 +53,7 @@ class Command(object):
         Developers creating new command base classes (such as
         :class:`Lister` and :class:`ShowOne`) should override this
         method to wrap :meth:`take_action`.
+
+        Return the value returned by :method:`take_action` or 0.
         """
-        self.take_action(parsed_args)
-        return 0
+        return self.take_action(parsed_args) or 0

cliff/tests/test_command.py

@@ -7,7 +7,7 @@ class TestCommand(Command):
     """
 
     def take_action(self, parsed_args):
-        return
+        return 42
 
 
 def test_get_description():
@@ -25,3 +25,8 @@ def test_get_parser():
 def test_get_name():
     cmd = TestCommand(None, None, cmd_name='object action')
     assert cmd.cmd_name == 'object action'
+
+
+def test_run_return():
+    cmd = TestCommand(None, None, cmd_name='object action')
+    assert cmd.run(None) == 42