@Test
  public void testReplaceWithNullValue() {
    region.create("3", null);
    assertEquals(false, region.replace("3", "foobar", "three"));
    assertEquals(true, region.replace("3", null, "three"));
    assertEquals(true, region.replace("3", "three", "3"));
    assertEquals(false, region.replace("3", null, "3"));
    region.invalidate("3");
    assertEquals(false, region.replace("3", "foobar", "three"));
    assertEquals(true, region.replace("3", null, "three"));
  }
Test the replace method with an entry that has overflowed to disk.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/ReplaceWithOverflowJUnitTest.java