ColumnBuffer { private void add(long timestamp, byte[] v) { timeStamps.add(timestamp); values.add(v); } ColumnBuffer(); void add(Key k, byte[] vByte); void add(Key k, Value v); void copyTo(ColumnBuffer dest, LongPredicate timestampTest); void clear(); int size(); Key getKey(int pos); Value getValue(int pos);  }
@Test public void testDifferentKeys() { ColumnBuffer columnBuffer = new ColumnBuffer(); columnBuffer.add(new Key("row1"), new Value()); try { columnBuffer.add(new Key("row2"), new Value()); Assert.fail(); } catch (IllegalArgumentException e) { } }