         let system = Driver.system(
             initialState: "initial",
             reduce: { oldState, append in
-                return  oldState + append
+                oldState + append
             },
             feedback: feedbackLoop, feedbackLoop, feedbackLoop)
 
-        let result = (try?
-            system
-                .asObservable()
-                .timeout(0.5, other: Observable.empty(), scheduler: MainScheduler.instance)
-                .toBlocking(timeout: 3.0)
-                .toArray()
-            ) ?? []
+        let result = (
+            try?
+                system
+                .asObservable()
+                .timeout(0.5, other: Observable.empty(), scheduler: MainScheduler.instance)
+                .toBlocking(timeout: 3.0)
+                .toArray()) ?? []
 
         XCTAssertTrue(result[1].contains("_a") || result[1].contains("_b"))
         XCTAssertTrue(result[2].contains("_a") || result[2].contains("_b"))

                    }
                }
                return Bindings(subscriptions: [], mutations: [results])
            })

        let result = (try?
            system
                .asObservable()
                .take(4)
                .timeout(0.5, other: Observable.empty(), scheduler: MainScheduler.instance)
                .toBlocking(timeout: 3.0)
                .toArray()
            ) ?? []

        XCTAssertEqual(result, [
            "initial",
            "initial_a",
            "initial_a_b",
            "initial_a_b_c"
            ])
    }
    func testBindingsAreNotDisposedWhenNoMutationsAreSpecifiedOnDriverSystem() {
        typealias State = Int
        typealias Mutation = Int

        let system = Driver.system(
            initialState: "initial",
            reduce: { oldState, append in
                oldState + append
            },
            feedback: RxFeedback.bind { stateAndScheduler in
                let results = stateAndScheduler.flatMap { state -> Signal<String> in
                    if state == "initial" {
                        return Signal.just("_a").delay(0.01)
