     }
     #endif
 
-    static var allTests: [(String, (ObservableWithLatestFromTest_) -> () -> ())] { return [
+    static var allTests: [(String, (ObservableWithLatestFromTest_) -> () -> Void)] { return [
     ("testWithLatestFrom_Simple1", ObservableWithLatestFromTest.testWithLatestFrom_Simple1),
     ("testWithLatestFrom_TwoObservablesWithImmediateValues", ObservableWithLatestFromTest.testWithLatestFrom_TwoObservablesWithImmediateValues),
     ("testWithLatestFrom_Simple2", ObservableWithLatestFromTest.testWithLatestFrom_Simple2),

    }
    #endif

    static var allTests: [(String, (HistoricalSchedulerTest_) -> () -> ())] { return [
    ("testHistoricalScheduler_initialClock", HistoricalSchedulerTest.testHistoricalScheduler_initialClock),
    ("testHistoricalScheduler_start", HistoricalSchedulerTest.testHistoricalScheduler_start),
    ("testHistoricalScheduler_disposeStart", HistoricalSchedulerTest.testHistoricalScheduler_disposeStart),

    }
    #endif

    static var allTests: [(String, (ObservableObserveOnTest_) -> () -> Void)] { return [
    ("testObserveOnDispatchQueue_DoesPerformWorkOnQueue", ObservableObserveOnTest.testObserveOnDispatchQueue_DoesPerformWorkOnQueue),
    ("testObserveOnDispatchQueue_DeadlockErrorImmediately", ObservableObserveOnTest.testObserveOnDispatchQueue_DeadlockErrorImmediately),
    ("testObserveOnDispatchQueue_DeadlockEmpty", ObservableObserveOnTest.testObserveOnDispatchQueue_DeadlockEmpty),
