NodeSet: fix fromall() to raise proper exception

fromall() should raise NodeSetExternalError in case of group resolution
error.

Closes #263.

Change-Id: I5937d6acc85e8c5b8ad6c3a61e5da4e9e89310a0

Author: thiell

lib/ClusterShell/NodeSet.py

@@ -1246,10 +1246,16 @@ def fromall(cls, groupsource=None, autostep=None, resolver=None):
         """Class method that returns a new NodeSet with all nodes from optional
         groupsource."""
         inst = NodeSet(autostep=autostep, resolver=resolver)
-        if not inst._resolver:
-            raise NodeSetExternalError("No node group resolver")
-        # Fill this nodeset with all nodes found by resolver
-        inst.updaten(inst._parser.all_nodes(groupsource))
+        try:
+            if not inst._resolver:
+                raise NodeSetExternalError("Group resolver is not defined")
+            else:
+                # fill this nodeset with all nodes found by resolver
+                inst.updaten(inst._parser.all_nodes(groupsource))
+        except NodeUtils.GroupResolverError, exc:
+            errmsg = "Group source error (%s: %s)" % (exc.__class__.__name__,
+                                                      exc)
+            raise NodeSetExternalError(errmsg)
         return inst
 
     def __getstate__(self):

tests/NodeSetGroupTest.py

@@ -192,6 +192,10 @@ def testAllNoResolver(self):
         self.assertRaises(NodeSetExternalError, NodeSet.fromall,
                           resolver=RESOLVER_NOGROUP)
 
+        # Also test with a nonfunctional resolver (#263)
+        res = GroupResolver()
+        self.assertRaises(NodeSetExternalError, NodeSet.fromall, resolver=res)
+
     def testGroupsNoResolver(self):
         """test NodeSet.groups() with no resolver"""
         nodeset = NodeSet("foo", resolver=RESOLVER_NOGROUP)