public ImmutableSet<String> loadAllMessageStreams(final StreamPermissions streamPermissions) {
        return allStreamsProvider.get()
                // Unless explicitly queried, exclude event and failure indices by default
                // Having these indices in every search, makes sorting almost impossible
                // because it triggers https://github.com/Graylog2/graylog2-server/issues/6378
                // TODO: this filter could be removed, once we implement https://github.com/Graylog2/graylog2-server/issues/6490
                .filter(id -> !NON_MESSAGE_STREAM_IDS.contains(id))
                .filter(streamPermissions::canReadStream)
                .collect(ImmutableSet.toImmutableSet());
    }
@Test
    public void returnsEmptyListIfNoStreamsFound() {
        final PermittedStreams sut = new PermittedStreams(() -> java.util.stream.Stream.of("oans", "zwoa", "gsuffa"));
        ImmutableSet<String> result = sut.loadAllMessageStreams(id -> false);
        assertThat(result).isEmpty();
    }