public function testClearFilters()
 {
     $this->object->setIndex(new TestIndex());
     $this->assertInstanceOf(FilterAttribute::class, $this->object->getFilter('bob'));
     $this->assertInstanceOf(FilterAttribute::class, $this->object->getFilter('age'));
     $this->assertInstanceOf(FilterAttribute::class, $this->object->getFilter('gender'));
     $this->assertCount(3, $this->object->getFilters());
     $this->object->clearFilters();
     $this->assertCount(0, $this->object->getFilters());
 }