contains() public method

Check whether or not the collection contains the named asset.
public contains ( string $name ) : boolean
$name string The name of the asset you want.
return boolean
 public function testRemove()
 {
     $collection = new AssetCollection(['libs.js', 'all.css'], $this->factory);
     $this->assertNull($collection->remove('libs.js'));
     $this->assertFalse($collection->contains('libs.js'));
     $this->assertNull($collection->get('libs.js'));
     foreach ($collection as $item) {
         $this->assertNotEquals('libs.js', $item->name());
     }
 }