public async Task AllConfigShowTestAsync()
{
// act
_controller.ShowAllConfigs();
// assert
var configsFile = await _storageService.ReadFileAsStringAsync(Constants.ConfigsFileName);
var configModel = JsonConvert.DeserializeObject <ConfigModel>(configsFile);
var expectedString = JsonConvert.SerializeObject(configModel, Formatting.Indented);
Assert.Equal(expectedString, _stringWriter.ToString().Trim());
}