### Question:
BitSetDocumentVisibilityFilterCacheStrategy extends DocumentVisibilityFilterCacheStrategy { public static boolean isFullyEmpty(OpenBitSet bitSet, long cardinality) { if (cardinality == 0) { return true; } return false; } BitSetDocumentVisibilityFilterCacheStrategy(); @Override DocIdSet getDocIdSet(String fieldName, BytesRef term, AtomicReader reader); @Override Builder createBuilder(String fieldName, BytesRef term, final AtomicReader reader); static DocIdSet getFullyEmptyDocIdSet(int maxDoc); static DocIdSetIterator getFullyEmptyDocIdSetIterator(int maxDoc); static Bits getFullyEmptyBits(int maxDoc); static DocIdSet getFullySetDocIdSet(int maxDoc); static DocIdSetIterator getFullySetDocIdSetIterator(int maxDoc); static Bits getFullySetBits(int maxDoc); static boolean isFullyEmpty(OpenBitSet bitSet, long cardinality); static boolean isFullySet(int maxDoc, OpenBitSet bitSet, long cardinality); static SegmentReader getSegmentReader(IndexReader indexReader); @Override String toString(); static final DocumentVisibilityFilterCacheStrategy INSTANCE; }### Answer:
@Test public void testIdFullyEmpty1() { int maxDoc = 10; OpenBitSet bitSet = new OpenBitSet(maxDoc); assertTrue(BitSetDocumentVisibilityFilterCacheStrategy.isFullyEmpty(bitSet, bitSet.cardinality())); }
@Test public void testIdFullyEmpty2() { int maxDoc = 10; OpenBitSet bitSet = new OpenBitSet(maxDoc); bitSet.set(3); assertFalse(BitSetDocumentVisibilityFilterCacheStrategy.isFullyEmpty(bitSet, bitSet.cardinality())); }