public function testEvery()
{
$set = new Set();
$set->add('hello', 'world', 'this', 'is', 'a', 'test');
$this->assertTrue($set->every(function ($item) {
return \is_string($item);
}));
$set->add(1);
$this->assertFalse($set->every(function ($item) {
return \is_string($item);
}));
}
