@Test
  public void testNoFaults() {
    DiskRegionStats diskStats = diskRegion.getStats();
    EvictionCounters lruStats = getLRUStats(region);

    IntStream.range(0, MAX_ENTRIES + 1).forEach((i) -> region.put(i, "value"));

    long firstEvictions = lruStats.getEvictions();
    long firstReads = diskStats.getReads();

    IntStream.range(1, MAX_ENTRIES + 1).forEach((key) -> {
      region.get(key);
      assertEquals("Key " + key + " caused an eviction", firstEvictions, lruStats.getEvictions());
      assertEquals("Key " + key + " caused an eviction", firstReads, diskStats.getReads());
    });
  }
Overflows a region and makes sure that gets of recently-used objects do not cause faults.
geode-core/src/integrationTest/java/org/apache/geode/cache30/DiskRegionIntegrationTest.java