shoc-backend/Api.SeaHavenIndustries.Tests/SendMessageTests.cs

using System.Net;
using Api.SeaHavenIndustries.Helper;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Moq;
using SendGrid;
using SendGrid.Helpers.Mail;
using Xunit;

namespace Api.SeaHavenIndustries.Tests;

public sealed class SendMessageTests
{
    private const string Recipient = "taylor@example.com";
    private const string Subject = "You're invited to Seahaven";
    private const string RejectionBody = "{\"errors\":[{\"message\":\"taylor@example.com does not exist\"}]}";

    [Theory]
    [InlineData(HttpStatusCode.OK, true)]
    [InlineData(HttpStatusCode.Accepted, true)]
    [InlineData(HttpStatusCode.BadRequest, false)]
    [InlineData(HttpStatusCode.Unauthorized, false)]
    [InlineData(HttpStatusCode.TooManyRequests, false)]
    [InlineData(HttpStatusCode.InternalServerError, false)]
    public async Task EverySendPath_ReportsDeliveryOnlyForASuccessStatus(HttpStatusCode status, bool delivered)
    {
        var sender = new StubbedSendMessage(status, new CapturingLogger());

        Assert.Equal(delivered, await sender.SendEMail(Recipient, Subject, "<p>Hi</p>"));
        Assert.Equal(delivered, await sender.SendEmailAsync(Recipient, Subject, "<p>Hi</p>"));
        Assert.Equal(delivered, await sender.SendEMailAttachment(Recipient, Subject, new byte[] { 1, 2, 3 }));
        Assert.Equal(delivered, await sender.SendDispatchEmail(Recipient, Subject, "<p>Hi</p>", null));
    }

    [Fact]
    public async Task ARejectedSend_LogsOnlyTheStatusCode()
    {
        var logger = new CapturingLogger();
        var sender = new StubbedSendMessage(HttpStatusCode.BadRequest, logger);

        Assert.False(await sender.SendEMail(Recipient, Subject, "<p>secret link</p>"));

        var entry = Assert.Single(logger.Entries);
        Assert.Contains("400", entry);
        Assert.DoesNotContain(Recipient, entry);
        Assert.DoesNotContain(Subject, entry);
        Assert.DoesNotContain("secret link", entry);
        Assert.DoesNotContain("errors", entry);
    }

    [Fact]
    public async Task AFailedSend_LogsOnlyTheExceptionType()
    {
        var logger = new CapturingLogger();
        var sender = new StubbedSendMessage(
            new HttpRequestException($"could not reach SendGrid for {Recipient}"),
            logger);

        Assert.False(await sender.SendEMail(Recipient, Subject, "<p>Hi</p>"));

        var entry = Assert.Single(logger.Entries);
        Assert.Contains(nameof(HttpRequestException), entry);
        Assert.DoesNotContain(Recipient, entry);
    }

    private sealed class StubbedSendMessage : SendMessage
    {
        private readonly Mock<ISendGridClient> _client = new();

        public StubbedSendMessage(HttpStatusCode status, ILogger<SendMessage> logger)
            : base(new ConfigurationBuilder().Build(), logger)
        {
            _client
                .Setup(client => client.SendEmailAsync(It.IsAny<SendGridMessage>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(() => new Response(status, new StringContent(RejectionBody), null));
        }

        public StubbedSendMessage(Exception failure, ILogger<SendMessage> logger)
            : base(new ConfigurationBuilder().Build(), logger)
        {
            _client
                .Setup(client => client.SendEmailAsync(It.IsAny<SendGridMessage>(), It.IsAny<CancellationToken>()))
                .ThrowsAsync(failure);
        }

        protected override ISendGridClient CreateClient(string? apiKey) => _client.Object;
    }

    private sealed class CapturingLogger : ILogger<SendMessage>
    {
        public List<string> Entries { get; } = new();

        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;

        public bool IsEnabled(LogLevel logLevel) => true;

        public void Log<TState>(
            LogLevel logLevel,
            EventId eventId,
            TState state,
            Exception? exception,
            Func<TState, Exception?, string> formatter) =>
            Entries.Add($"{formatter(state, exception)} {exception}");
    }
}