DigitalData.MessagingService/tests/DigitalData.MessagingService.Tests/Integration/EmailSenderTests.cs

using DigitalData.MessagingService.Application.Common.Dto;
using DigitalData.MessagingService.Client;
using DigitalData.MessagingService.Domain.Entities;

namespace DigitalData.MessagingService.Tests.Integration;

/// <summary>
/// xUnit collection that serializes all <see cref="EmailSenderTests"/> so they share
/// the same process-wide static state of <see cref="EmailSender.LazyProvider"/>.
/// </summary>
[CollectionDefinition(Name)]
public sealed class EmailSenderCollection : ICollectionFixture<EmailSenderFixture>
{
    public const string Name = "EmailSender";
}

/// <summary>
/// Fixture that connects <see cref="EmailSender"/> once before all tests in the collection run.
/// </summary>
public sealed class EmailSenderFixture
{
    public EmailSenderFixture()
    {
        // EmailSender is a static class with a Lazy<IServiceProvider>.
        // ConnectRabbitMq can only be called successfully once per process.
        if (!EmailSender.IsConnected)
        {
            EmailSender.ConnectRabbitMq(cfg =>
            {
                cfg.HostName = RabbitMqTestConfig.HostName;
                cfg.Port = RabbitMqTestConfig.Port;
                cfg.UserName = RabbitMqTestConfig.UserName;
                cfg.Password = RabbitMqTestConfig.Password;
                cfg.VirtualHost = RabbitMqTestConfig.VirtualHost;
                cfg.QueueName = RabbitMqTestConfig.QueueName;
                cfg.ExchangeName = RabbitMqTestConfig.ExchangeName;
                cfg.RoutingKey = RabbitMqTestConfig.RoutingKey;
                cfg.DlqQueueName = RabbitMqTestConfig.DlqQueueName;
                cfg.DlqExchangeName = RabbitMqTestConfig.DlqExchangeName;
                cfg.DlqRoutingKey = RabbitMqTestConfig.DlqRoutingKey;
            });
        }
    }
}

/// <summary>
/// Integration tests for the <see cref="EmailSender"/> static client.
/// All tests run inside <see cref="EmailSenderCollection"/> to share the single
/// static connection established by <see cref="EmailSenderFixture"/>.
/// </summary>
[Collection(EmailSenderCollection.Name)]
public sealed class EmailSenderTests
{
    [Fact]
    public void IsConnected_AfterConnectRabbitMq_ReturnsTrue()
    {
        Assert.True(EmailSender.IsConnected);
    }

    [Fact]
    public void ConnectRabbitMq_WhenAlreadyConnected_WithThrowException_ThrowsInvalidOperationException()
    {
        Assert.Throws<InvalidOperationException>(() =>
            EmailSender.ConnectRabbitMq(cfg => { }, OnReconnect.ThrowException));
    }

    [Fact]
    public void ConnectRabbitMq_WhenAlreadyConnected_WithIgnore_DoesNotThrow()
    {
        var exception = Record.Exception(() =>
            EmailSender.ConnectRabbitMq(cfg => { }, OnReconnect.Ignore));

        Assert.Null(exception);
    }

    [Fact]
    public async Task Send_WithValidEmail_DoesNotThrow()
    {
        var email = new EmailContext
        {
            Sender = new EmailAccount { Username = "test@example.com", Password = "password", SmtpServer = "smtp.example.com" },
            Recipients = ["hakanttek@gmail.com"],
            Subject = "EmailSender.Send Integration Test",
            Body = "<p>Sent via EmailSender static client.</p>",
            IsHtml = true,
        };

        var exception = await Record.ExceptionAsync(() => EmailSender.Send(email));

        Assert.Null(exception);
    }

    [Fact]
    public async Task Send_WithPlainTextBody_DoesNotThrow()
    {
        var email = new EmailContext
        {
            Sender = new EmailAccount { Username = "test@example.com", Password = "password", SmtpServer = "smtp.example.com" },
            Recipients = ["hakanttek@gmail.com"],
            Subject = "Plain Text Test",
            Body = "This is a plain text email.",
            IsHtml = false
        };

        var exception = await Record.ExceptionAsync(() => EmailSender.Send(email));

        Assert.Null(exception);
    }
}