Rx\Functional\Operator\DistinctUntilChangedTest::distinct_until_changed_key_selector_throws PHP Method

    public function distinct_until_changed_key_selector_throws()
    {
        $xs = $this->createHotObservable([onNext(150, 1), onNext(210, 2), onCompleted(250)]);
        $results = $this->scheduler->startWithCreate(function () use($xs) {
            return $xs->distinctUntilKeyChanged(function ($x) {
                throw new \Exception('ex');
            });
        });
        $this->assertMessages([onError(210, new \Exception('ex'))], $results->getMessages());
    }