--- a/devtools/client/memory/test/unit/test_action-clear-snapshots_06.js
+++ b/devtools/client/memory/test/unit/test_action-clear-snapshots_06.js
@@ -34,18 +34,22 @@ add_task(function* () {
   yield waitUntilSnapshotState(store,
     [states.SAVED_CENSUS, states.SAVED_CENSUS]);
 
   dispatch(toggleDiffing());
   dispatch(selectSnapshotForDiffingAndRefresh(heapWorker,
                                               getState().snapshots[0]));
   dispatch(selectSnapshotForDiffingAndRefresh(heapWorker,
                                               getState().snapshots[1]));
+
   ok(getState().diffing, "We should be in diffing view");
 
+  yield waitUntilAction(store, actions.TAKE_CENSUS_DIFF_END);
+  ok(true, "Received TAKE_CENSUS_DIFF_END action");
+
   ok(true, "Dispatch clearSnapshots action");
   let deleteEvents = Promise.all([
     waitUntilAction(store, actions.DELETE_SNAPSHOTS_START),
     waitUntilAction(store, actions.DELETE_SNAPSHOTS_END)
   ]);
   dispatch(clearSnapshots(heapWorker));
   yield deleteEvents;
   ok(true, "received delete snapshots events");