failing to unlock android screen while testing

I get an error message while testing an Android app related to scren lock while testing. I took from SO posts this code to enable the unlock screen, and so implementing this method

public void callApplicationOnCreate(Application app) {
        // Unlock the screen
        KeyguardManager keyguard = (KeyguardManager) app.getSystemService(Context.KEYGUARD_SERVICE);
        keyguard.newKeyguardLock(getClass().getSimpleName()).disableKeyguard();

        // Start a wake lock
        PowerManager power = (PowerManager) app.getSystemService(Context.POWER_SERVICE);
        mWakeLock = power.newWakeLock(PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP | PowerManager.ON_AFTER_RELEASE, getClass().getSimpleName());
        mWakeLock.acquire();

        super.callApplicationOnCreate(app);
    } 

Here's the error message

java.lang.RuntimeException: Waited for the root of the view hierarchy to have window focus and not be requesting layout for over 10 seconds. If you specified a non default root matcher, it may be picking a root that never takes focus. Otherwise, something is seriously wrong

Am I wrong ? Is there any other way to do that ?