hrynco-notification-service/HrynCo.NotificationService.Services.Tests/EmailProcessing/NotificationDeliveryErrorFormatterTests.cs

namespace HrynCo.NotificationService.Services.Tests.EmailProcessing;

using HrynCo.NotificationService.Worker.Services.EmailProcessing;
using System.Net.Mail;
using System.Net.Sockets;

public sealed class NotificationDeliveryErrorFormatterTests
{
    [Fact]
    public void Format_UsesInnermostMessageAndRemovesLineBreaks()
    {
        var exception = new InvalidOperationException(
            "outer",
            new Exception("provider failed\r\nretry rejected"));

        string result = NotificationDeliveryErrorFormatter.Format(exception);

        Assert.Equal(
            "Notification delivery failed after all retry attempts (provider failed retry rejected).",
            result);
    }

    [Fact]
    public void Format_UnresolvedSmtpHost_AddsSafeChannelContext()
    {
        var socketException = new SocketException((int)SocketError.HostNotFound);
        var exception = new SmtpException("Failure sending mail.", socketException);

        string result = NotificationDeliveryErrorFormatter.Format(exception);

        Assert.Equal(
            $"SMTP delivery failed after all retry attempts: the configured SMTP server host could not be resolved ({socketException.Message}).",
            result);
    }

    [Fact]
    public void Format_RefusedSmtpConnection_AddsSafeChannelContext()
    {
        var socketException = new SocketException((int)SocketError.ConnectionRefused);
        var exception = new SmtpException("Failure sending mail.", socketException);

        string result = NotificationDeliveryErrorFormatter.Format(exception);

        Assert.Equal(
            $"SMTP delivery failed after all retry attempts: the configured SMTP server refused the connection ({socketException.Message}).",
            result);
    }

    [Fact]
    public void Format_LongError_IsBoundedToOutboxColumnLength()
    {
        var exception = new Exception(new string('x', 2100));

        string result = NotificationDeliveryErrorFormatter.Format(exception);

        Assert.Equal(2000, result.Length);
    }
}