undoManager.clear();
assertFalse( "clearing the Undo manager should result in the impossibility to undo anything", undoManager.isUndoPossible() );
assertFalse( "clearing the Undo manager should result in the impossibility to redo anything", undoManager.isRedoPossible() );
m_undoListener = new UndoListener();
undoManager.addUndoManagerListener( m_undoListener );
impl_testSingleModification( undoManager );
impl_testMultipleModifications( undoManager );
impl_testCustomUndoActions( undoManager );
impl_testLocking( undoManager );