public function testDeleteScenario()
 {
     $model = new RedisItem();
     $model->scenario = 'delete';
     $model->setAttributes(['key' => 'tfx_string']);
     $this->assertTrue($model->validate());
     $model->setAttributes(['key' => 'T^R$%&^R^VTYFFt']);
     $this->assertFalse($model->validate());
     $this->assertTrue($model->hasErrors('key'));
     $model->setAttributes(['db' => 1, 'ttl' => 500, 'key' => null]);
     $this->assertFalse($model->validate());
     $this->assertTrue($model->hasErrors('key'));
 }