Rx\Functional\Operator\ConcatMapTest::concatMapTo_Then_Complete_Task PHP Метод

    public function concatMapTo_Then_Complete_Task()
    {
        $xs = Observable::fromArray([4, 3, 2, 1]);
        $ys = Observable::just(42);
        $results = [];
        $completed = false;
        $xs->concatMapTo($ys)->subscribeCallback(function ($x) use(&$results) {
            $results[] = $x;
        }, function ($e) {
            $this->fail();
        }, function () use(&$completed) {
            $completed = true;
        });
        $this->assertTrue($completed);
        $this->assertEquals([42, 42, 42, 42], $results);
    }