Approve app.config

VerifyConfig.cs

        private static void VerifyConfig(string path, Action<Configuration> action)
        {
            using (var t = new TempFile(Path.GetRandomFileName()))
            {
                File.Copy(path, t.File.FullName, true);
                var fileMap = new ExeConfigurationFileMap { ExeConfigFilename = t.File.FullName };
                var exeConfig = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
                action.Invoke(exeConfig);
                var config = File.ReadAllText(exeConfig.FilePath);
                Approvals.Verify(config);
            }
        }