code: @Test public void testStore() throws Exception {
    PersistKeyValueImpl impl=injector.getInstance(PersistKeyValueImpl.class);
    Map<String,String> map=impl.getAllKeyValues();
    assertEquals(0,map.size());
    impl.put("key1","value1");
    impl.put("key2","value2");
    map=impl.getAllKeyValues();
    assertEquals(2,map.size());
    assertEquals("value1",impl.getValue("key1"));
    assertEquals("value2",impl.getValue("key2"));
    assertEquals(map.get("key1"),impl.getValue("key1"));
    impl.put("key1","value1-2");
    assertEquals("value1-2",impl.getValue("key1"));
    assertEquals(2,map.size());
    StringBuilder largeValueBuilder=new StringBuilder();
    for (int i=0; i < 320; i++) {
      largeValueBuilder.append("0123456789");
    }
    String largeValue=largeValueBuilder.toString();
    impl.put("key3",largeValue);
    assertEquals(largeValue,impl.getValue("key3"));
  }
  