update() public method

Update a model document.
public update ( ) : mixed
return mixed
 /**
  * @test
  */
 public function it_throw_an_exception_if_trying_to_update_a_model_with_exits_false()
 {
     $connection = \Mockery::mock(Connection::class);
     $model = new PersistenceModelTest();
     $model->exists = false;
     $this->setExpectedException('Exception');
     $persistence = new EloquentPersistence($connection);
     $persistence->model($model);
     $persistence->update();
 }