Pinq\Tests\Integration\Traversable\UnionTest::testThatUnionMaintainsReferences PHP Method

    public function testThatUnionMaintainsReferences(\Pinq\ITraversable $traversable)
    {
        $data = $this->makeRefs(range('a', 'f'));
        $traversable->union($data)->iterate(function (&$i) {
            $i = "{$i}-";
        });
        $this->assertSame('a-b-c-d-e-f-', implode('', $data));
    }