tweak tests/error output

integration/test_grid_manager.py

@@ -166,6 +166,7 @@ def test_reject_storage_server(reactor, request, alice, storage_nodes):
         )
         assert False, "Should get a failure"
     except Exception as e:
-        # XXX but how to tell if we failed for the right reason?
-        # (should get UploadUnhappinessError)
-        print("failure expected: {}".format(e))
+        # depending on the full output being in the error-message
+        # here; see util.py
+        assert 'UploadUnhappinessError' in str(e)
+        print("found expected UploadUnhappinessError")

integration/util.py

@@ -53,7 +53,13 @@ class _CollectOutputProtocol(ProcessProtocol):
 
     def processExited(self, reason):
         if not isinstance(reason.value, ProcessDone):
-            self.done.errback(reason)
+            #self.done.errback(reason)
+            self.done.errback(RuntimeError(
+                "Process failed: {}\nOutput:\n{}".format(
+                    reason,
+                    self.output.getvalue(),
+                )
+            ))
 
     def outReceived(self, data):
         self.output.write(data)