### Question:
ScrollPaneAdapter implements GriffonPivotAdapter, org.apache.pivot.wtk.ScrollPaneListener { public void verticalScrollBarPolicyChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.ScrollPane.ScrollBarPolicy arg1) { if (verticalScrollBarPolicyChanged != null) { verticalScrollBarPolicyChanged.call(arg0, arg1); } }  CallableWithArgs<Void> getHorizontalScrollBarPolicyChanged(); CallableWithArgs<Void> getRowHeaderChanged(); CallableWithArgs<Void> getVerticalScrollBarPolicyChanged(); CallableWithArgs<Void> getColumnHeaderChanged(); CallableWithArgs<Void> getCornerChanged(); void setHorizontalScrollBarPolicyChanged(CallableWithArgs<Void> horizontalScrollBarPolicyChanged); void setRowHeaderChanged(CallableWithArgs<Void> rowHeaderChanged); void setVerticalScrollBarPolicyChanged(CallableWithArgs<Void> verticalScrollBarPolicyChanged); void setColumnHeaderChanged(CallableWithArgs<Void> columnHeaderChanged); void setCornerChanged(CallableWithArgs<Void> cornerChanged); void horizontalScrollBarPolicyChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.ScrollPane.ScrollBarPolicy arg1); void rowHeaderChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.Component arg1); void verticalScrollBarPolicyChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.ScrollPane.ScrollBarPolicy arg1); void columnHeaderChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.Component arg1); void cornerChanged(org.apache.pivot.wtk.ScrollPane arg0, org.apache.pivot.wtk.Component arg1);  }### Answer:
@Test public void testVerticalScrollBarPolicyChanged() { final boolean[] invoked = new boolean[1]; CallableWithArgs<Void> callable = new CallableWithArgs<Void>() { public Void call(Object... args) { invoked[0] = true; return null; } }; assertNull(adapter.getVerticalScrollBarPolicyChanged()); adapter.verticalScrollBarPolicyChanged(null, null); assertFalse(invoked[0]); adapter.setVerticalScrollBarPolicyChanged(callable); adapter.verticalScrollBarPolicyChanged(null, null); assertTrue(invoked[0]); }