Mock IConfigurationSection para retornar matriz de string

Question

Usando esta resposta para simular os IConfigurationmétodos de um aplicativo ASP.NET Core.

Preciso simular um IConfigurationSectionpara retornar um stringarray.

Minha classe de configuração é assim:

public class LoggingConfiguration
{
    public string ApplicationName { get; set; }
    public string[] Loggers { get; set; }
}

appsettings.json

{
    "Logging": {
        "LoggingConfiguration": {
              "ApplicationName": "Some app",
              "Loggers":  [ "DiskLogger", "MemoryLogger"],
              "DiskLogger": {
                  "SomeSettingOne" : "setting",
                  "SomeSettingTwo" : "setting",
               },
              "MemoryLogger": {
                  "AnotherSetting": "...",
               }
       }

Ao configurar os mocks - eu tenho dois problemas.

1. Não consigo descobrir como zombar de um IConfigurationSectionque retornaria string[]( loggers)
2. Estou recebendo uma exceção quando tento configurar o GetChildren()método noLoggingSectionMock

public void Setup()
{
    var applicationNameConfigurationSectionMock = new Mock<IConfigurationSection>();
    applicationNameConfigurationSectionMock.Setup(m => m.Value).Returns(TestingApplicationName);

    var loggerNamesConfigurationSectionMock = new Mock<IConfigurationSection>();
    loggerNamesConfigurationSectionMock.Setup(m => m.GetChildren()).Returns(GetLoggerNamesSection);

    //Throwing Method Not Found exception
    LoggingSectionMock.Setup(m => m.GetChildren()).Returns(new List<IConfigurationSection>
        {applicationNameConfigurationSectionMock.Object, loggerNamesConfigurationSectionMock.Object});

    ConfigurationMock.Setup(m => m.GetSection($"{Logging}:{LoggingConfiguration}"))
        .Returns(() => LoggingSectionMock.Object);
}

private IEnumerable<IConfigurationSection> GetLoggerNamesSection()
{
    var loggerNamesConfigurationSections = new List<IConfigurationSection>();
    LoggerNames.ToList().ForEach(loggerName =>
    {
        var configSectionMock = new Mock<IConfigurationSection>();
        configSectionMock.Setup(m => m.Value).Returns(loggerName);
        loggerNamesConfigurationSections.Add(configSectionMock.Object);
    });
    return loggerNamesConfigurationSections;
}

Answer 1

Como alternativa, você pode tirar proveito de ConfigurationBuilder's AddInMemoryCollection:

Fornecedor de configuração de memória de referência

Configuração

IConfiguration configRoot = new ConfigurationBuilder()
    .AddInMemoryCollection(new Dictionary<string, string>
    {
        { "ApplicationName", "App" }, 
        { "Loggers:0", "1" },
        { "Loggers:1", "2" },
        { "Loggers:2", "3" }
    })
    .Build();

Uso

LoggingConfiguration config = configRoot.Get<LoggingConfiguration>();