### Question:
PrimitiveLongCollections { public static int count( PrimitiveLongIterator iterator ) { int count = 0; for ( ; iterator.hasNext(); iterator.next(), count++ ) { } return count; } private  PrimitiveLongCollections(); static PrimitiveLongIterator iterator( final long... items ); static PrimitiveLongIterator concat( PrimitiveLongIterator... primitiveLongIterators ); static PrimitiveLongIterator concat( Iterable<PrimitiveLongIterator> primitiveLongIterators ); static PrimitiveLongIterator filter( PrimitiveLongIterator source, final LongPredicate filter ); static PrimitiveLongResourceIterator filter( PrimitiveLongResourceIterator source, final LongPredicate filter ); static PrimitiveLongIterator range( long start, long end ); static long single( PrimitiveLongIterator iterator, long defaultItem ); static int indexOf( PrimitiveLongIterator iterator, long item ); static PrimitiveLongSet asSet( Collection<Long> collection ); static PrimitiveLongSet asSet( PrimitiveLongIterator iterator ); static PrimitiveLongSet asSet( PrimitiveLongSet set ); static PrimitiveLongSet asSet( long... values ); static PrimitiveLongObjectMap<T> copy( PrimitiveLongObjectMap<T> original ); static int count( PrimitiveLongIterator iterator ); static long[] asArray( PrimitiveLongIterator iterator ); static long[] asArray( Iterator<Long> iterator ); static PrimitiveLongIterator emptyIterator(); static PrimitiveLongIterator toPrimitiveIterator( final Iterator<Long> iterator ); static PrimitiveLongSet emptySet(); static PrimitiveLongSet setOf( long... values ); static Iterator<T> map( final LongFunction<T> mapFunction, final PrimitiveLongIterator source ); static List<Long> asList( PrimitiveLongIterator iterator ); static Iterator<Long> toIterator( final PrimitiveLongIterator primIterator ); static PrimitiveLongResourceIterator resourceIterator( final PrimitiveLongIterator iterator,
            final Resource resource ); static Set<Long> toSet( PrimitiveLongSet set ); static Set<Long> toSet( PrimitiveLongIterator iterator ); static long[] deduplicate( long[] values ); static final long[] EMPTY_LONG_ARRAY; }### Answer:
@Test void count() { PrimitiveLongIterator items = PrimitiveLongCollections.iterator( 1, 2, 3 ); int count = PrimitiveLongCollections.count( items ); assertEquals( 3, count ); }