Rx\Functional\Operator\ConcatTest::testConcatAllError PHP Method

    public function testConcatAllError()
    {
        $sources = Observable::fromArray([Observable::just(0), Observable::error(new \Exception()), Observable::just(2), Observable::just(3)]);
        $res = [];
        $error = false;
        $completed = false;
        $sources->concatAll()->subscribeCallback(function ($x) use(&$res) {
            $res[] = $x;
        }, function ($e) use(&$res, &$error) {
            $this->assertEquals([0], $res);
            $error = true;
        }, function () use(&$completed) {
            $completed = true;
        });
        $this->assertTrue($error);
        $this->assertFalse($completed);
    }