[Feature] Use Interface to be able make mockable tests

I'm using this nice lib as my setting handler, the problem is that as there is no interface, I cannot mock it (e.g. to verify if some items are changing with specific data).

also after changing the class that is auto-generated to code below, I couldn't inject it to my project :((

`public class Settings : IAppSettings { private static ISettings AppSetting => CrossSettings.Current;

    #region Settings Constants
    public const string BaseUrlKey = "baseurl";
    public static readonly string BaseUrlDefault = "http://localhost:88/";
    public const string JustAvailableProductKey = "justAvailable";
    public static readonly bool JustAvailableDefault = false;

    #endregion

    public void SetValue(string key, int value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public void SetValue(string key, string value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public void SetValue(string key, long value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public void SetValue(string key, float value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public void SetValue(string key, bool value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public void SetValue(string key, decimal value)
    {
        AppSetting.AddOrUpdateValue(key, value);
    }

    public int GetValue(string key, int defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }

    public string GetValue(string key, string defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }

    public float GetValue(string key, float defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }

    public long GetValue(string key, long defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }

    public bool GetValue(string key, bool defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }

    public decimal GetValue(string key, decimal defaultValue)
    {
        return AppSetting.GetValueOrDefault(key, defaultValue);
    }
}`

And IAppSetting.cs:

public interface IAppSettings { void SetValue(string key, int value); void SetValue(string key, string value); void SetValue(string key, float value); void SetValue(string key, long value); void SetValue(string key, bool value); void SetValue(string key, decimal value); int GetValue(string key, int defaultValue); string GetValue(string key, string defaultValue); float GetValue(string key, float defaultValue); long GetValue(string key, long defaultValue); bool GetValue(string key, bool defaultValue); decimal GetValue(string key, decimal defaultValue); }

Now I can mock setting I wish in my tests and verify if methods are called with specific items.

Please add this kind of handling settings in future versions to be testable. I'm not sure if there is a better way to do that.

thanks for your helpful lib :)

jamesmontemagno / SettingsPlugin

[Feature] Use Interface to be able make mockable tests #70