public void AndSettingValueIsNull_ThenThrowException()
        {
            var settingKey = "MyBadSetting";
            var sut        = new AppConfigSettingsProvider(new PropertiesSettingsProvider());

            sut.GetNullableSetting(settingKey).Should().BeNull();
        }
        public void ThenReturnSettingValue()
        {
            var settingKey   = "MySetting";
            var settingValue = "hello world";
            var sut          = new AppConfigSettingsProvider(new PropertiesSettingsProvider());

            Properties.Settings.Default[settingKey] = settingValue;

            var setting = sut.GetNullableSetting(settingKey);

            setting.Should().Be(settingValue);
        }