fix AsyncResult.join

list of lists not passed properly to chain

Author: minrk

ipyparallel/client/asyncresult.py

@@ -416,8 +416,8 @@ def join(cls, *async_results):
             client=first._client,
             fname=first._fname,
             return_exceptions=first._return_exceptions,
-            children=list(chain(ar._children for ar in async_results)),
-            targets=list(chain(ar._targets for ar in async_results)),
+            children=list(chain(*(ar._children for ar in async_results))),
+            targets=list(chain(*(ar._targets for ar in async_results))),
             owner=False,
         )
 

ipyparallel/tests/test_asyncresult.py

@@ -461,6 +461,8 @@ def test_split(self):
         # get doubly-nested lists because these are
         split_results = [ar.get(timeout=10) for ar in children]
         assert split_results == result
+        joined = ipp.AsyncResult.join(*children)
+        assert joined.get(timeout=1) == result
 
     def test_split_map_result(self):
         v = self.client.load_balanced_view()