Feat: 전역 예외 핸들러 구현

src/InterviewAssistant.ApiService/Middlewares/GlobalExceptionHandler.cs

@@ -0,0 +1,33 @@
+using System.Net;
+using System.Text.Json;
+using Microsoft.AspNetCore.Diagnostics;
+
+namespace InterviewAssistant.ApiService.Middlewares;
+
+/// <summary>
+/// 전역 예외 처리기
+/// </summary>
+public class GlobalExceptionHandler(ILogger<GlobalExceptionHandler> logger) : IExceptionHandler
+{
+    public async ValueTask<bool> TryHandleAsync(
+        HttpContext httpContext, 
+        Exception exception, 
+        CancellationToken cancellationToken)
+    {
+        logger.LogError(exception, "예외 발생: {Message}", exception.Message);
+
+        var response = new
+        {
+            error = "서버 오류가 발생했습니다.",
+            message = exception.Message,
+            timestamp = DateTime.UtcNow
+        };
+
+        httpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
+        httpContext.Response.ContentType = "application/json";
+
+        await httpContext.Response.WriteAsync(JsonSerializer.Serialize(response), cancellationToken);
+
+        return true;
+    }
+}

src/InterviewAssistant.ApiService/Program.cs

@@ -6,6 +6,7 @@
 using InterviewAssistant.ApiService.Data;
 using InterviewAssistant.ApiService.Repositories;
 using InterviewAssistant.ApiService.Extensions;
+using InterviewAssistant.ApiService.Middlewares;
 
 using Microsoft.SemanticKernel;
 using Microsoft.EntityFrameworkCore;
@@ -49,6 +50,7 @@
     return McpClientFactory.CreateAsync(transport).GetAwaiter().GetResult(); 
 });
 
+builder.Services.AddExceptionHandler<GlobalExceptionHandler>();
 
 builder.Services.AddSingleton<Kernel>(sp =>
 {

test/InterviewAssistant.ApiService.Tests/Middlewares/GlobalExceptionHandlerTests.cs

@@ -0,0 +1,99 @@
+using System.Net;
+using System.Text.Json;
+
+using InterviewAssistant.ApiService.Middlewares;
+
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+using NSubstitute;
+
+using Shouldly;
+
+namespace InterviewAssistant.ApiService.Tests.Middlewares;
+
+[TestFixture]
+public class GlobalExceptionHandlerTests
+{
+    private ILogger<GlobalExceptionHandler> _logger;
+    private GlobalExceptionHandler _handler;
+    private DefaultHttpContext _httpContext;
+
+    [SetUp]
+    public void Setup()
+    {
+        _logger = Substitute.For<ILogger<GlobalExceptionHandler>>();
+        _handler = new GlobalExceptionHandler(_logger);
+        _httpContext = new DefaultHttpContext();
+        _httpContext.Response.Body = new MemoryStream();
+    }
+
+    [Test]
+    public async Task TryHandleAsync_WithException_ShouldReturnTrueAndSetCorrectResponse()
+    {
+        // Arrange
+        var exception = new InvalidOperationException("테스트 예외");
+
+        // Act
+        var result = await _handler.TryHandleAsync(_httpContext, exception, CancellationToken.None);
+
+        // Assert
+        result.ShouldBeTrue();
+        _httpContext.Response.StatusCode.ShouldBe(500);
+        _httpContext.Response.ContentType.ShouldBe("application/json");
+
+        // 응답 내용 확인
+        _httpContext.Response.Body.Position = 0;
+        var responseContent = await new StreamReader(_httpContext.Response.Body).ReadToEndAsync();
+        var responseObject = JsonSerializer.Deserialize<JsonElement>(responseContent);
+
+        responseObject.GetProperty("error").GetString().ShouldBe("서버 오류가 발생했습니다.");
+        responseObject.GetProperty("message").GetString().ShouldBe("테스트 예외");
+        responseObject.TryGetProperty("timestamp", out _).ShouldBeTrue();
+    }
+
+    [Test]
+    [TestCase(typeof(NullReferenceException), "Null reference")]
+    [TestCase(typeof(FileNotFoundException), "File not found")]
+    [TestCase(typeof(UnauthorizedAccessException), "Access denied")]
+    public async Task TryHandleAsync_WithDifferentExceptions_ShouldHandleCorrectly(Type exceptionType, string message)
+    {
+        // Arrange
+        var exception = (Exception)Activator.CreateInstance(exceptionType, message)!;
+
+        // Act
+        var result = await _handler.TryHandleAsync(_httpContext, exception, CancellationToken.None);
+
+        // Assert
+        result.ShouldBeTrue();
+        _httpContext.Response.StatusCode.ShouldBe(500);
+
+        _httpContext.Response.Body.Position = 0;
+        var responseContent = await new StreamReader(_httpContext.Response.Body).ReadToEndAsync();
+        var responseObject = JsonSerializer.Deserialize<JsonElement>(responseContent);
+
+        responseObject.GetProperty("message").GetString().ShouldBe(message);
+    }
+
+    [Test]
+    public async Task TryHandleAsync_ShouldGenerateValidJsonResponse()
+    {
+        // Arrange
+        var exception = new InvalidOperationException("JSON 검증");
+
+        // Act
+        await _handler.TryHandleAsync(_httpContext, exception, CancellationToken.None);
+
+        // Assert
+        _httpContext.Response.Body.Position = 0;
+        var responseContent = await new StreamReader(_httpContext.Response.Body).ReadToEndAsync();
+
+        // JSON 유효성 검증
+        Should.NotThrow(() => JsonSerializer.Deserialize<JsonElement>(responseContent));
+
+        var responseObject = JsonSerializer.Deserialize<JsonElement>(responseContent);
+        responseObject.TryGetProperty("error", out _).ShouldBeTrue();
+        responseObject.TryGetProperty("message", out _).ShouldBeTrue();
+        responseObject.TryGetProperty("timestamp", out _).ShouldBeTrue();
+    }
+}