ChatBot/ChatBot.Tests/Services/Telegram/TelegramErrorHandlerTests.cs

using ChatBot.Services.Telegram.Services;
using ChatBot.Tests.TestUtilities;
using Microsoft.Extensions.Logging;
using Moq;
using Telegram.Bot;
using Telegram.Bot.Exceptions;

namespace ChatBot.Tests.Services.Telegram;

public class TelegramErrorHandlerTests : UnitTestBase
{
    private readonly Mock<ILogger<TelegramErrorHandler>> _loggerMock;
    private readonly Mock<ITelegramBotClient> _botClientMock;
    private readonly TelegramErrorHandler _errorHandler;

    public TelegramErrorHandlerTests()
    {
        _loggerMock = new Mock<ILogger<TelegramErrorHandler>>();
        _botClientMock = new Mock<ITelegramBotClient>();
        _errorHandler = new TelegramErrorHandler(_loggerMock.Object);
    }

    [Fact]
    public void Constructor_ShouldCreateInstance()
    {
        // Act & Assert
        Assert.NotNull(_errorHandler);
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithApiRequestException_ShouldLogErrorWithFormattedMessage()
    {
        // Arrange
        var errorCode = 400;
        var errorMessage = "Bad Request: chat not found";
        var apiException = new ApiRequestException(errorMessage, errorCode);
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            apiException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains($"Telegram API Error:\n[{errorCode}]\n{errorMessage}")
                    ),
                    apiException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Theory]
    [InlineData(400, "Bad Request")]
    [InlineData(401, "Unauthorized")]
    [InlineData(403, "Forbidden")]
    [InlineData(404, "Not Found")]
    [InlineData(429, "Too Many Requests")]
    [InlineData(500, "Internal Server Error")]
    public async Task HandlePollingErrorAsync_WithDifferentApiErrorCodes_ShouldLogCorrectFormat(
        int errorCode,
        string errorMessage
    )
    {
        // Arrange
        var apiException = new ApiRequestException(errorMessage, errorCode);
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            apiException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains($"Telegram API Error:\n[{errorCode}]\n{errorMessage}")
                    ),
                    apiException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithGenericException_ShouldLogExceptionToString()
    {
        // Arrange
        var genericException = new InvalidOperationException("Something went wrong");
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            genericException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains("System.InvalidOperationException: Something went wrong")
                    ),
                    genericException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithTimeoutException_ShouldLogTimeoutException()
    {
        // Arrange
        var timeoutException = new TimeoutException("Request timed out");
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            timeoutException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!.Contains("System.TimeoutException: Request timed out")
                    ),
                    timeoutException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithHttpRequestException_ShouldLogHttpRequestException()
    {
        // Arrange
        var httpException = new HttpRequestException("Network error occurred");
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            httpException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains(
                                    "System.Net.Http.HttpRequestException: Network error occurred"
                                )
                    ),
                    httpException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithCancelledToken_ShouldCompleteSuccessfully()
    {
        // Arrange
        var exception = new InvalidOperationException("Test exception");
        using var cancellationTokenSource = new CancellationTokenSource();
        await cancellationTokenSource.CancelAsync();
        var cancelledToken = cancellationTokenSource.Token;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            exception,
            cancelledToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.IsAny<It.IsAnyType>(),
                    exception,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_ShouldReturnCompletedTask()
    {
        // Arrange
        var exception = new Exception("Test exception");
        var cancellationToken = CancellationToken.None;

        // Act
        var task = _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            exception,
            cancellationToken
        );

        // Assert
        Assert.True(task.IsCompleted);
        await task; // Ensure no exceptions are thrown
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithNestedException_ShouldLogOuterException()
    {
        // Arrange
        var innerException = new ArgumentException("Inner exception");
        var outerException = new InvalidOperationException("Outer exception", innerException);
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            outerException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains("System.InvalidOperationException: Outer exception")
                    ),
                    outerException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }

    [Fact]
    public async Task HandlePollingErrorAsync_WithAggregateException_ShouldLogAggregateException()
    {
        // Arrange
        var exceptions = new Exception[]
        {
            new InvalidOperationException("First exception"),
            new ArgumentException("Second exception"),
        };
        var aggregateException = new AggregateException("Multiple exceptions occurred", exceptions);
        var cancellationToken = CancellationToken.None;

        // Act
        await _errorHandler.HandlePollingErrorAsync(
            _botClientMock.Object,
            aggregateException,
            cancellationToken
        );

        // Assert
        _loggerMock.Verify(
            x =>
                x.Log(
                    LogLevel.Error,
                    It.IsAny<EventId>(),
                    It.Is<It.IsAnyType>(
                        (v, t) =>
                            v.ToString()!
                                .Contains("System.AggregateException: Multiple exceptions occurred")
                    ),
                    aggregateException,
                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
                ),
            Times.Once
        );
    }
}