public async Task EnumerateFiles()
        {
            var css   = Substitute.For <IConfigurationSettingCollection>();
            var shell = Substitute.For <ICoreShell>();

            string folder = @"C:\";
            string file1  = @"C:\Settings.R";
            string file2  = @"C:\Debug.Settings.R";
            string file3  = @"C:\foo.bar";
            var    fs     = Substitute.For <IFileSystem>();

            fs.GetFileSystemEntries(folder, Arg.Any <string>(), SearchOption.AllDirectories).Returns(new string[] { file1, file2, file3 });
            fs.DirectoryExists(Arg.Any <string>()).Returns(false);
            fs.FileExists(file1).Returns(true);
            fs.FileExists(file2).Returns(true);
            fs.FileExists(file3).Returns(true);

            var model = new SettingsPageViewModel(css, shell, fs);
            await model.SetProjectPathAsync(folder, null);

            model.CurrentFile.Should().Be("~/Settings.R");
            model.Files.Should().HaveCount(2);
            model.Files.ToArray()[0].Should().Be("~/Settings.R");
            model.Files.ToArray()[1].Should().Be("~/Debug.Settings.R");
        }
        public async Task CreateNewFile()
        {
            var css   = new ConfigurationSettingCollection();
            var shell = Substitute.For <ICoreShell>();
            var fs    = Substitute.For <IFileSystem>();

            var    model = new SettingsPageViewModel(css, shell, fs);
            string file  = Path.GetTempFileName();
            await model.SetProjectPathAsync("C:\\", null);

            model.CreateNewSettingsFile();
            model.CurrentFile.Should().Be("~/Settings.R");
        }
        public async Task EmptyViewModel()
        {
            var css   = Substitute.For <IConfigurationSettingCollection>();
            var shell = Substitute.For <ICoreShell>();

            string file = Path.GetTempFileName();
            var    fs   = Substitute.For <IFileSystem>();

            fs.GetFileSystemEntries(file, Arg.Any <string>(), SearchOption.AllDirectories).Returns(new string[] { file });
            fs.DirectoryExists(file).Returns(false);
            fs.FileExists(file).Returns(true);

            var model = new SettingsPageViewModel(css, shell, fs);
            await model.SetProjectPathAsync(Path.GetDirectoryName(file), null);

            model.CurrentFile.Should().BeNull();
            (await model.SaveAsync()).Should().BeFalse(); // nothing should happen
        }
        public async Task LoadSave()
        {
            var settings = Substitute.For <IConfigurationSettingCollection>();
            var shell    = Substitute.For <ICoreShell>();
            var fs       = Substitute.For <IFileSystem>();
            var pp       = Substitute.For <IRProjectProperties>();

            fs.GetFileSystemEntries(null, null, SearchOption.AllDirectories).ReturnsForAnyArgs(new string[] { @"C:\Settings22.R" });
            pp.GetSettingsFileAsync().Returns(Task.FromResult("~/Settings22.R"));

            var model = new SettingsPageViewModel(settings, shell, fs);
            await model.SetProjectPathAsync(@"C:\", pp);

            await pp.Received().GetSettingsFileAsync();

            model.CurrentFile.Should().Be("~/Settings22.R");

            (await model.SaveAsync()).Should().BeTrue();
            settings.Received().Save(@"C:\Settings22.R");
        }