### Question:
NodeValueSortKey extends NodeValue implements Comparable<NodeValueSortKey> { @Override public boolean isSortKey() { return Boolean.TRUE; } NodeValueSortKey(final String string, final String collation);  NodeValueSortKey(final String string, final String collation, Node n); @Override boolean isSortKey(); @Override NodeValueSortKey getSortKey(); @Override String getString(); @Override String asString(); String getCollation(); @Override void visit(NodeValueVisitor visitor); @Override String toString(); @Override int compareTo(NodeValueSortKey other);  }### Answer:
@Test public void testCreateNodeValueSortKey() { NodeValueSortKey nv = new NodeValueSortKey("", null); assertTrue(nv.isSortKey()); }