Unit test Symfony Messenger
Problem was resolved by setting a return with an Envelope object.
$this->messageBus->expects(self::exactly(3)) ->method('dispatch') ->withConsecutive( self::isInstanceOf(GetVideoMetadataMessage::class), self::isInstanceOf(CheckVideoMessage::class), self::isInstanceOf(GenerateThumbnailMessage::class) ) ->willReturn(new Symfony\Component\Messenger\Envelope($message));