diff --git a/RxCocoa/Common/CocoaUnits/Driver/Driver.swift b/RxCocoa/Common/CocoaUnits/Driver/Driver.swift
index b6855094..821e7e26 100644
--- a/RxCocoa/Common/CocoaUnits/Driver/Driver.swift
+++ b/RxCocoa/Common/CocoaUnits/Driver/Driver.swift
@@ -99,7 +99,7 @@ extension Driver {
     */
     @warn_unused_result(message="http://git.io/rxs.uo")
     public static func empty() -> Driver<E> {
-        return Driver(raw: Observable.empty().subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.empty().subscribeOn(driverSubscribeOnScheduler()))
     }
     
     /**
@@ -109,7 +109,7 @@ extension Driver {
     */
     @warn_unused_result(message="http://git.io/rxs.uo")
     public static func never() -> Driver<E> {
-        return Driver(raw: Observable.never().subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.never().subscribeOn(driverSubscribeOnScheduler()))
     }
     
     /**
@@ -120,7 +120,7 @@ extension Driver {
     */
     @warn_unused_result(message="http://git.io/rxs.uo")
     public static func just(element: E) -> Driver<E> {
-        return Driver(raw: Observable.just(element).subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.just(element).subscribeOn(driverSubscribeOnScheduler()))
     }
 
     /**
@@ -137,7 +137,7 @@ extension Driver {
 
     @warn_unused_result(message="http://git.io/rxs.uo")
     public static func of(elements: E ...) -> Driver<E> {
-        let source = elements.toObservable().subscribeOn(driverSubscribeOnScheduler)
+        let source = elements.toObservable().subscribeOn(driverSubscribeOnScheduler())
         return Driver(raw: source)
     }
     
@@ -147,17 +147,17 @@ public struct Drive {
 
     @available(*, deprecated=2.0.0, message="Please use `Driver.empty` (`r` at the end).")
     public static func empty<E>() -> Driver<E> {
-        return Driver(raw: Observable.empty().subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.empty().subscribeOn(driverSubscribeOnScheduler()))
     }
 
     @available(*, deprecated=2.0.0, message="Please use `Driver.never` (`r` at the end).")
     public static func never<E>() -> Driver<E> {
-        return Driver(raw: Observable.never().subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.never().subscribeOn(driverSubscribeOnScheduler()))
     }
 
     @available(*, deprecated=2.0.0, message="Please use `Driver.just` (`r` at the end).")
     public static func just<E>(element: E) -> Driver<E> {
-        return Driver(raw: Observable.just(element).subscribeOn(driverSubscribeOnScheduler))
+        return Driver(raw: Observable.just(element).subscribeOn(driverSubscribeOnScheduler()))
     }
 
     @available(*, deprecated=2.0.0, message="Please use `Driver.deferred` (`r` at the end).")
@@ -168,7 +168,7 @@ public struct Drive {
 
     @available(*, deprecated=2.0.0, message="Please use `Driver.of` (`r` at the end).")
     public static func sequenceOf<E>(elements: E ...) -> Driver<E> {
-        let source = elements.toObservable().subscribeOn(driverSubscribeOnScheduler)
+        let source = elements.toObservable().subscribeOn(driverSubscribeOnScheduler())
         return Driver(raw: source)
     }
     
@@ -186,8 +186,8 @@ func driveOnScheduler(scheduler: SchedulerType, action: () -> ()) {
     let originalObserveOnScheduler = driverObserveOnScheduler
     let originalSubscribeOnScheduler = driverSubscribeOnScheduler
 
-    driverObserveOnScheduler = scheduler
-    driverSubscribeOnScheduler = scheduler
+    driverObserveOnScheduler = { scheduler }
+    driverSubscribeOnScheduler = { scheduler }
 
     action()
 
@@ -195,5 +195,6 @@ func driveOnScheduler(scheduler: SchedulerType, action: () -> ()) {
     driverSubscribeOnScheduler = originalSubscribeOnScheduler
 }
 
-var driverObserveOnScheduler: SchedulerType = MainScheduler.instance
-var driverSubscribeOnScheduler: SchedulerType = ConcurrentMainScheduler.instance
+// using lambas disables optimizations that break @testable (another Swift bug)
+var driverObserveOnScheduler: () -> SchedulerType = { MainScheduler.instance }
+var driverSubscribeOnScheduler: () -> SchedulerType = { ConcurrentMainScheduler.instance }
diff --git a/RxCocoa/Common/CocoaUnits/Driver/ObservableConvertibleType+Driver.swift b/RxCocoa/Common/CocoaUnits/Driver/ObservableConvertibleType+Driver.swift
index 5bc3f437..05eee133 100644
--- a/RxCocoa/Common/CocoaUnits/Driver/ObservableConvertibleType+Driver.swift
+++ b/RxCocoa/Common/CocoaUnits/Driver/ObservableConvertibleType+Driver.swift
@@ -22,7 +22,7 @@ extension ObservableConvertibleType {
     public func asDriver(onErrorJustReturn onErrorJustReturn: E) -> Driver<E> {
         let source = self
             .asObservable()
-            .observeOn(driverObserveOnScheduler)
+            .observeOn(driverObserveOnScheduler())
             .catchErrorJustReturn(onErrorJustReturn)
         return Driver(source)
     }
@@ -37,7 +37,7 @@ extension ObservableConvertibleType {
     public func asDriver(onErrorDriveWith onErrorDriveWith: Driver<E>) -> Driver<E> {
         let source = self
             .asObservable()
-            .observeOn(driverObserveOnScheduler)
+            .observeOn(driverObserveOnScheduler())
             .catchError { _ in
                 onErrorDriveWith.asObservable()
             }
@@ -54,7 +54,7 @@ extension ObservableConvertibleType {
     public func asDriver(onErrorRecover onErrorRecover: (error: ErrorType) -> Driver<E>) -> Driver<E> {
         let source = self
             .asObservable()
-            .observeOn(driverObserveOnScheduler)
+            .observeOn(driverObserveOnScheduler())
             .catchError { error in
                 onErrorRecover(error: error).asObservable()
             }
diff --git a/RxCocoa/Common/CocoaUnits/Driver/Variable+Driver.swift b/RxCocoa/Common/CocoaUnits/Driver/Variable+Driver.swift
index 8d683b09..d915fd20 100644
--- a/RxCocoa/Common/CocoaUnits/Driver/Variable+Driver.swift
+++ b/RxCocoa/Common/CocoaUnits/Driver/Variable+Driver.swift
@@ -20,7 +20,7 @@ extension Variable {
     @warn_unused_result(message="http://git.io/rxs.uo")
     public func asDriver() -> Driver<E> {
         let source = self
-            .observeOn(driverObserveOnScheduler)
+            .observeOn(driverObserveOnScheduler())
         return Driver(source)
     }
 }
\ No newline at end of file
diff --git a/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift b/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
index a758e3e4..c69c0364 100644
--- a/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
+++ b/RxExample/RxExample-iOSTests/TestScheduler+MarbleTests.swift
@@ -42,7 +42,7 @@ extension TestScheduler {
 
     */
     func parseEventsAndTimes<T>(timeline: String, values: [String: T], errors: [String: ErrorType] = [:]) -> [[Recorded<Event<T>>]] {
-        print("parsing: \(timeline)")
+        //print("parsing: \(timeline)")
         typealias RecordedEvent = Recorded<Event<T>>
         let timelines = timeline.componentsSeparatedByString("|")
 
@@ -82,7 +82,7 @@ extension TestScheduler {
                     return (state.time + tickIncrement, state.events + [nextEvent])
                 }
 
-                print("parsed: \(events)")
+                //print("parsed: \(events)")
                 return events
             }
     }
diff --git a/RxExample/RxExample.xcodeproj/xcshareddata/xcschemes/RxExample-iOS.xcscheme b/RxExample/RxExample.xcodeproj/xcshareddata/xcschemes/RxExample-iOS.xcscheme
index 9df0a481..6728d0d1 100644
--- a/RxExample/RxExample.xcodeproj/xcshareddata/xcschemes/RxExample-iOS.xcscheme
+++ b/RxExample/RxExample.xcodeproj/xcshareddata/xcschemes/RxExample-iOS.xcscheme
@@ -23,7 +23,7 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release-Tests"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES">