@Test
  public void testInstanceOfDiskRegion() {
    DiskRegionProperties diskRegionProperties = new DiskRegionProperties();
    diskRegionProperties.setDiskDirs(diskDirs); // diskDirs is an array of four diskDirs
    diskRegionProperties.setRolling(true);

    DiskStoreFactory diskStoreFactory2 = toDiskStoreFactory(diskRegionProperties);

    DiskStore diskStore = createDiskStoreWithSizeInBytes(diskStoreName, diskStoreFactory2);

    Region<?, ?> region = createRegion(regionName, diskStoreName, true, true, false, false, 0);

    region.destroyRegion();
    closeDiskStore(diskStore);

    diskRegionProperties.setDiskDirs(diskDirs); // diskDirs is an array of four diskDirs
    diskRegionProperties.setRolling(false);

    DiskStoreFactory diskStoreFactory1 = toDiskStoreFactory(diskRegionProperties);

    createDiskStoreWithSizeInBytes(diskStoreName, diskStoreFactory1);

    region = createRegion(regionName, diskStoreName, true, true, false, false, 0);

    region.destroyRegion();
    closeDiskStore(diskStore);

    diskRegionProperties.setRolling(false);
    diskRegionProperties.setDiskDirsAndSizes(new File[] {newFolder(uniqueName + "1")},
        new int[] {2048});

    DiskStoreFactory diskStoreFactory = toDiskStoreFactory(diskRegionProperties);

    createDiskStoreWithSizeInBytes(diskStoreName, diskStoreFactory);

    region = createRegion(regionName, diskStoreName, true, true, false, false, 0);

    region.destroyRegion();
    closeDiskStore(diskStore);

    diskRegionProperties.setRolling(false);
    diskRegionProperties.setMaxOplogSize(2048);
    File dir = newFolder(uniqueName + "2");
    diskRegionProperties.setDiskDirsAndSizes(new File[] {dir}, new int[] {1024});

    // TODO: test just rolls along? not sure of the value
  }
DiskRegionFactoryJUnitTest: Test for verifying DiskRegion or SimpleDiskRegion.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/DiskRegionJUnitTest.java