     }
 
     func testTransientNodes() {
+        let engine = AKEngine()
         let osc = AKOscillator()
         func exampleStart() {
             let env = AKAmplitudeEnvelope(osc)

// Copyright AudioKit. All Rights Reserved. Revision History at http://github.com/AudioKit/AudioKit/
@testable import AudioKit
import XCTest
import AVFoundation
import CAudioKit

class AKNodeTests: AKTestCase {

    let osc = AKOscillator()

    func testNodeBasic() {
        duration = 0.1
        XCTAssertNotNil(osc.avAudioUnit)
        osc.start()
        engine.output = osc
        AKTest()
    }

    func testNodeConnection() {
        osc.start()
        let verb = AKCostelloReverb(osc)
        engine.output = verb
        AKTest()
    }

    func testRedundantConnection() {

        let verb = AKCostelloReverb(osc)
        engine.output = verb

        let audio = engine.startTest(totalDuration: 0.1)
        audio.append(engine.render(duration: 0.1))
        testMD5(audio)

    }

    func testManyMixerConnections() {

        let engine = AKEngine()

        var oscs: [AKOscillator] = []
        for _ in 0..<16 {
            oscs.append(AKOscillator())
