### Question:
RedundancyCalculator { public static boolean canMergeSegments(Layout layout) { if (layout.getSegments().size() == 1) { return false; } else { final int firstSegmentIndex = 0; final int secondSegmentIndex = 1; return Sets.difference( layout.getSegments().get(secondSegmentIndex).getAllLogServers(), layout.getSegments().get(firstSegmentIndex).getAllLogServers()).isEmpty(); } }  Layout updateLayoutAfterRedundancyRestoration(
            List<TransferSegment> segments, Layout initLayout); static boolean canRestoreRedundancy(Layout layout, String server); static boolean canMergeSegments(Layout layout); static boolean canRestoreRedundancyOrMergeSegments(Layout layout, String server); ImmutableList<TransferSegment> createStateList(Layout layout, long trimMark); ImmutableList<TransferSegment> getTrimmedNotRestoredSegments(Layout layout, long trimMark); ImmutableList<TransferSegmentRange> prepareTransferWorkload(
            ImmutableList<TransferSegment> transferSegmentList,
            Optional<Long> committedTail);  }### Answer:
@Test public void testCanMergeSegmentsOneSegment() { LayoutSegment segment = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("localhost")))); assertThat(RedundancyCalculator .canMergeSegments(createTestLayout(Arrays.asList(segment)))).isFalse(); }
@Test public void testCanMergeSegmentsServersNonPresent() { LayoutSegment segment1 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("localhost", "B")))); LayoutSegment segment2 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("C", "A")))); assertThat(RedundancyCalculator .canMergeSegments(createTestLayout(Arrays.asList(segment1, segment2)))).isFalse(); }
@Test public void testCanMergeSegmentsServerNotPresent() { LayoutSegment segment1 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("localhost", "B")))); LayoutSegment segment2 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("C", "B", "localhost")))); assertThat(RedundancyCalculator .canMergeSegments(createTestLayout(Arrays.asList(segment1, segment2)))).isFalse(); }
@Test public void testCanMergeSegmentsDoMerge() { LayoutSegment segment1 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("localhost", "B")))); LayoutSegment segment2 = new LayoutSegment(CHAIN_REPLICATION, 0L, 1L, Arrays.asList(new LayoutStripe(Arrays.asList("B", "localhost")))); assertThat(RedundancyCalculator .canMergeSegments(createTestLayout(Arrays.asList(segment1, segment2)))).isTrue(); }