public function testThatExtendedClassIsMaintainedAfterLongQuery(\Pinq\ICollection $collection) { $collection = $collection->append([1, 2, 4, 5])->join([6, 7, 8, 9])->on(function () { return true; })->to(function ($a, $b) { return $a + $b; })->unique()->select(function ($i) { return $i * 10; })->indexBy(function ($i) { return $i; }); $this->assertExtended($collection); }