diff --git a/spec/unit/room.spec.js b/spec/unit/room.spec.js
index b98559ecf..a355f95fa 100644
--- a/spec/unit/room.spec.js
+++ b/spec/unit/room.spec.js
@@ -1411,4 +1411,27 @@ describe("Room", function() {
             expect(room.getMyMembership()).toEqual("join");
         });
     });
+
+    describe("guessDMUserId", function() {
+        it("should return first hero id",
+        async function() {
+            const room = new Room(roomId, null, userA);
+            room.setSummary({'m.heroes': [userB]});
+            expect(room.guessDMUserId()).toEqual(userB);
+        });
+        it("should return first member that isn't self",
+        async function() {
+            const room = new Room(roomId, null, userA);
+            room.addLiveEvents([utils.mkMembership({
+                user: userB, mship: "join",
+                room: roomId, event: true,
+            })]);
+            expect(room.guessDMUserId()).toEqual(userB);
+        });
+        it("should return self if only member present",
+        async function() {
+            const room = new Room(roomId, null, userA);
+            expect(room.guessDMUserId()).toEqual(userA);
+        });
+    });
 });