### Question:
VarBitMetricStore implements MetricStore { @Override public List<Point> getSeries(long uuid) { mu.readLock().lock(); try { VarBitTimeSeries s = series.get(uuid); if (s == null) { return Collections.emptyList(); } return s.read().getPoints(); } finally { mu.readLock().unlock(); } } VarBitMetricStore();  VarBitMetricStore(int initialSize); @Override List<Point> getSeries(long uuid); @Override void addPoint(long uuid, long ts, double val); @Override Map<String, Object> getStats(); @Override Map getSeriesMap(); @Override void close(); void setReadOnly(boolean readOnly); @Override boolean isReadOnly();  }### Answer:
@Test public void testEmpty() { MetricStore store = new VarBitMetricStore(); assertTrue(store.getSeries(1).isEmpty()); assertTrue(store.getSeries(2).isEmpty()); }