public void SaveAllTest()
        {
            // Arrange
            var type = "HomeController";
            var key = $"{type}.{CultureInfo.CurrentUICulture.Name}";
            var hostingEnvironmentTest = TestHostingEnvironment();
            var fileSystem = TestFileSytem();
            var cache = new JsonLocalizationCache(hostingEnvironmentTest, fileSystem.Object);

            //act
            var dict = new TranslationDictionary();
            dict["specific"] = new Translation() { str = "Culture specific", Added = new DateTime(1) };
            cache.TranslationDictionaries.TryAdd(key, dict);
            cache.Dirty = true;
            cache.SaveAll();
            //assert
            fileSystem.Verify(m => m.WriteAllText(It.IsAny<string>(), It.IsAny<string>()), Times.Once());
        }