add test for if notification doesn't exist on repository

test/resolvers/MutationResolverTests.test.ts

@@ -138,7 +138,19 @@ describe("MutationResolvers", () => {
     });
 
     it("fails if the notification doesn't exist", async () => {
+      const notificationInput = {
+        deviceId: "1",
+        shuttleId: "1",
+        stopId: "1",
+      }
 
+      const response = await getServerResponse(query, notificationInput);
+
+      assert(response.body.kind === "single");
+      expect(response.body.singleResult.errors).toBeUndefined();
+
+      const notificationResponse = response.body.singleResult.data?.cancelNotification as any;
+      expect(notificationResponse.success).toBe(false);
     });
   });
 });