public function testConcatEmptyReturn()
{
$e1 = $this->createHotObservable([onNext(150, 1), onCompleted(230)]);
$e2 = $this->createHotObservable([onNext(150, 1), onNext(240, 2), onCompleted(250)]);
$results = $this->scheduler->startWithCreate(function () use($e1, $e2) {
return $e1->concat($e2);
});
$this->assertMessages([onNext(240, 2), onCompleted(250)], $results->getMessages());
}