@Test public void testHasValidArea_nothingAdded() { assertFalse(tracker.hasValidArea()); }
boolean hasValidArea() { return area != null && !area.isEmpty(); }
GeometryTracker { boolean hasValidArea() { return area != null && !area.isEmpty(); } }
GeometryTracker { boolean hasValidArea() { return area != null && !area.isEmpty(); } GeometryTracker(); }
GeometryTracker { boolean hasValidArea() { return area != null && !area.isEmpty(); } GeometryTracker();  }
GeometryTracker { boolean hasValidArea() { return area != null && !area.isEmpty(); } GeometryTracker();   }