diff --git a/js/test/test-mux.js b/js/test/test-mux.js
index 88d6c03..f0644eb 100644
--- a/js/test/test-mux.js
+++ b/js/test/test-mux.js
@@ -256,4 +256,24 @@ describe('computeEvents', function () {
       expect(events.metaEvents.get(0).equals(Patch.emptyPatch)).to.be(true);
     });
   });
+
+  describe('for a no-op but nonempty patch', function () {
+    var oldM = new Mux.Mux();
+    var pid1 = oldM.addStream(Patch.assert(["fieldContents", "initial", 7])).pid;
+    var pid2 = oldM.addStream(Patch.sub(["fieldContents", __, __])).pid;
+    var newM = oldM.shallowCopy();
+    var updateStreamResult =
+	newM.updateStream(pid1,
+			  Patch.retract(["fieldContents", __, __])
+			  .andThen(Patch.assert(["fieldContents", "initial", 7])));
+    var events = Mux.computeEvents(oldM, newM, updateStreamResult);
+
+    it('should send an empty patch to the subscriber', function () {
+      expect(events.eventMap.size).to.be(1);
+      expect(events.eventMap.has(pid2)).to.be(true);
+      checkPrettyPatch(events.eventMap.get(pid2).strip(),
+		       ['::: nothing'],
+		       ['::: nothing']);
+    });
+  });
 });