Testing the ViewModels, how can I mock the SettingsRepository?

[fcogutierrez]

Which plugin does this impact:

• [ ] Battery
• [ ] Connectivity
• [ ] Contacts
• [ ] DeviceInfo
• [ ] ExternalMaps
• [ ] Geolocator
• [ ] Media
• [ ] Permissions
• [x] Settings
• [ ] Text To Speech
• [ ] Vibrate

Question:

How can I mock my static AppSettings class in my Unit tests?

I am doing this:

public static class AppSettings
{
    private const string EmailKey = "email_key";

    public static string Email
    {
        get { return SettingsRepository.GetValueOrDefault<string>(EmailKey, string.Empty); }
        set { SettingsRepository.AddOrUpdateValue<string>(EmailKey, value); }
    }

    private static ISettings SettingsRepository
    {
        get { return CrossSettings.Current; }
    }
}

Thanks a lot.

[jamesmontemagno]

You would just need to implement a different version of ISettings and then return it when you want to use that mock.

[fcogutierrez]

@jamesmontemagno, thanks but...how can I set my ISettings implementation instead of using CrossSettings.Current?

    private static ISettings SettingsRepository
    {
        get { return CrossSettings.Current; }
    }

[jamesmontemagno]

Simply implement it in a new class and then return it?

[fcogutierrez]

Yes, but how can I replace the CrossSettings.Current by my implementation?

[jamesmontemagno]

private static ISettings SettingsRepository
    {
        get { return new YourImplementation(); }
    }

[fcogutierrez]

Ok @jamesmontemagno , so I have my AppSettings class and my AppSettingsMock class:

• In the AppSettings I am using the CrossSettings.Current implementaiton.
• In the AppSettingsMock I am using a custom implementation of ISettings (new MockSettingsRepository()).

However, in my ViewModel (subject under test) I am doing:

        //some operations...
        Email = AppSettings.Email;
        Password = AppSettings.Password;
        //more operations...

And my question is...how can I use my AppSettingsMock instead of the AppSettings class in my test?

Thank you a lot for your help mr James :-) :+1: :+1:

[yairsz]

@fcogutierrez I believe you need to setup a form of iOC. For example in MVVMCross you could do this:

public static string Email
{
    get { 
         var settingsSvc = Mvx.Resolve<ISettingsService>();
         return settingsSvc.GetValueOrDefault<string>(EmailKey, string.Empty); 
}
    set { 
         var settingsSvc = Mvx.Resolve<ISettingsService>();
         settingsSvc .AddOrUpdateValue<string>(EmailKey, value); 
}
}