public function testPrepend()
{
$c = new Collection(['one', 'two', 'three', 'four']);
$this->assertEquals(['zero', 'one', 'two', 'three', 'four'], $c->prepend('zero')->all());
$c = new Collection(['one' => 1, 'two' => 2]);
$this->assertEquals(['zero' => 0, 'one' => 1, 'two' => 2], $c->prepend(0, 'zero')->all());
}
