MDC { public static void put(final String key, final Object value) { ThreadContext.put(key, value); } private  MDC(); @SuppressWarnings({ "rawtypes", "unchecked" }) static Hashtable getContext(); static Object get(final String key); static void put(final String key, final Object value); static void remove(final String key); static void clear();  }
@Test public void putValue() { MDC.put("pi", "3.14"); verify(provider).put("pi", "3.14"); }