shadows/framework/src/main/java/org/robolectric/shadows/ShadowDisplayManager.java
public static void changeDisplay(int displayId, String qualifiersStr) {
    DisplayInfo baseDisplayInfo = DisplayManagerGlobal.getInstance().getDisplayInfo(displayId);
    DisplayInfo displayInfo = createDisplayInfo(qualifiersStr, baseDisplayInfo);
    getShadowDisplayManagerGlobal().changeDisplay(displayId, displayInfo);
    shadowMainLooper().idle();
  }
public static void changeDisplay(int displayId, String qualifiersStr) {
    DisplayInfo baseDisplayInfo = DisplayManagerGlobal.getInstance().getDisplayInfo(displayId);
    DisplayInfo displayInfo = createDisplayInfo(qualifiersStr, baseDisplayInfo);
    getShadowDisplayManagerGlobal().changeDisplay(displayId, displayInfo);
    shadowMainLooper().idle();
  }
Changes properties of a simulated display. If `qualifiersStr` starts with a plus (`+`) sign,
the display's previous configuration is modified with the given qualifiers; otherwise defaults
are applied as described [here](http://robolectric.org/device-configuration/).

<p>Idles the main looper to ensure all listeners are notified.

@param displayId the display id to change
@param qualifiersStr the {@link Qualifiers} string representing characteristics of the new
display