### Question:
TransformingIterator extends WrappingIterator implements OptionDescriber { protected Key replaceKeyParts(Key originalKey, Text newColFam, Text newColQual, Text newColVis) { byte[] row = originalKey.getRowData().toArray(); byte[] cf = newColFam.getBytes(); byte[] cq = newColQual.getBytes(); byte[] cv = newColVis.getBytes(); long timestamp = originalKey.getTimestamp(); Key newKey = new Key(row, 0, row.length, cf, 0, newColFam.getLength(), cq, 0, newColQual.getLength(), cv, 0, newColVis.getLength(), timestamp); newKey.setDeleted(originalKey.isDeleted()); return newKey; }  @Override void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options,
      IteratorEnvironment env); @Override IteratorOptions describeOptions(); @Override boolean validateOptions(Map<String,String> options); @Override SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env); @Override boolean hasTop(); @Override Key getTopKey(); @Override Value getTopValue(); @Override void next(); @Override void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive); static void setAuthorizations(IteratorSetting config, Authorizations auths); static void setMaxBufferSize(IteratorSetting config, long maxBufferSize); static final String AUTH_OPT; static final String MAX_BUFFER_SIZE_OPT; }### Answer:
@Test public void testReplaceKeyParts() { TransformingIterator it = new IdentityKeyTransformingIterator(); Key originalKey = new Key("r", "cf", "cq", "cv", 42); originalKey.setDeleted(true); Key newKey = it.replaceColumnFamily(originalKey, new Text("test")); assertEquals(createDeleteKey("r", "test", "cq", "cv", 42), newKey); newKey = it.replaceColumnQualifier(originalKey, new Text("test")); assertEquals(createDeleteKey("r", "cf", "test", "cv", 42), newKey); newKey = it.replaceColumnVisibility(originalKey, new Text("test")); assertEquals(createDeleteKey("r", "cf", "cq", "test", 42), newKey); newKey = it.replaceKeyParts(originalKey, new Text("testCQ"), new Text("testCV")); assertEquals(createDeleteKey("r", "cf", "testCQ", "testCV", 42), newKey); newKey = it.replaceKeyParts(originalKey, new Text("testCF"), new Text("testCQ"), new Text("testCV")); assertEquals(createDeleteKey("r", "testCF", "testCQ", "testCV", 42), newKey); }