### Question:
Phial { public static void removeKey(String key) { DEFAULT_CATEGORY.removeKey(key); }  static void setKey(String key, String value); static void setKey(@NonNull String key, @Nullable Object value); static void removeKey(String key); static Category category(String name); static void removeCategory(String name); static void addSaver(Saver saver); static void removeSaver(Saver saver);  }### Answer:
@Test public void removeKey_call_removeKey_for_all_savers() throws Exception { Phial.removeKey("key"); savers.forEach(saver -> verify(saver).remove(anyString(), eq("key")) ); }