avocado.tree: Allow combining of debug and non-debug TreeNodes

The TreeNodeDebug needs the origin to work properly. This patch allows
combyining debug and non-debug trees by supplying "Unknown" origin when
to non-debug TreeNodes.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

avocado/core/plugins/multiplexer.py

@@ -12,7 +12,6 @@
 # Copyright: Red Hat Inc. 2013-2014
 # Author: Lucas Meneghel Rodrigues <lmr@redhat.com>
 
-import os
 import sys
 
 from avocado.core.plugins import plugin
@@ -91,7 +90,10 @@ class Multiplexer(plugin.Plugin):
             else:
                 color = output.term_support.LOWLIGHT
                 cend = output.term_support.ENDC
-                paths = ', '.join(["%s%s@%s%s" % (_.name, color, _.yaml, cend)
+                paths = ', '.join(["%s%s@%s%s" % (_.name, color,
+                                                  getattr(_, 'yaml',
+                                                          "Unknown"),
+                                                  cend)
                                    for _ in tpl])
             view.notify(event='minor', msg='%sVariant %s:    %s' %
                         (('\n' if args.contents else ''), index + 1, paths))

avocado/core/tree.py

@@ -670,7 +670,7 @@ class TreeNodeDebug(TreeNode):  # only container pylint: disable=R0903
         Override origin with the one from other tree. Updated/Newly set values
         are going to use this location as origin.
         """
-        if hasattr(other, 'yaml'):
+        if hasattr(other, 'yaml') and other.yaml:
             srcyaml = os.path.relpath(other.yaml)
             # when we use TreeNodeDebug, value is always ValueDict
             self.value.yaml_per_key.update(other.value.yaml_per_key)    # pylint: disable=E1101