@Test
  public void testDiskProxy() throws Exception {
    AttributesFactory af = new AttributesFactory();
    af.setDataPolicy(DataPolicy.EMPTY);
    af.setEvictionAttributes(
        EvictionAttributes.createLRUEntryAttributes(1, EvictionAction.OVERFLOW_TO_DISK));
    try {
      af.create();
      fail("expected IllegalStateException");
    } catch (IllegalStateException ignored) {
    }
  }
Make sure a disk region and proxy play nice.
geode-core/src/integrationTest/java/org/apache/geode/cache/ProxyJUnitTest.java