Features/exceptions pipeline integration (#308)

web/backend/Shared/Shared.Application.Tests/Behaviors/UnhandledExceptionLoggingBehaviorTests.cs

@@ -0,0 +1,111 @@
+using FluentAssertions;
+using FluentValidation;
+using FluentValidation.Results;
+using MediatR;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Shared.Application.Behaviors;
+
+namespace Shared.Application.Tests.Behaviors;
+
+public class UnhandledExceptionLoggingBehaviorTests
+{
+    private readonly Mock<
+        ILogger<UnhandledExceptionLoggingBehavior<TestRequest, TestResponse>>
+    > _loggerMock = new();
+
+    private UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> CreateBehavior() =>
+        new(_loggerMock.Object);
+
+    [Fact]
+    public async Task Handle_WhenHandlerThrowsGenericException_LogsOnceAndRethrows()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        InvalidOperationException thrown = new("boom");
+        RequestHandlerDelegate<TestResponse> next = () => throw thrown;
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<InvalidOperationException>())
+            .Which.Should()
+            .BeSameAs(thrown);
+        VerifyLogError(Times.Once());
+    }
+
+    [Fact]
+    public async Task Handle_WhenValidationExceptionThrown_DoesNotLogAndRethrows()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        ValidationException thrown = new([new ValidationFailure("Username", "is required")]);
+        RequestHandlerDelegate<TestResponse> next = () => throw thrown;
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<ValidationException>()).Which.Should().BeSameAs(thrown);
+        VerifyLogError(Times.Never());
+    }
+
+    [Fact]
+    public async Task Handle_WhenHandlerSucceeds_DoesNotLogAndReturnsResponse()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        TestResponse response = new("ok");
+        RequestHandlerDelegate<TestResponse> next = () => Task.FromResult(response);
+
+        TestResponse result = await behavior.Handle(request, next, CancellationToken.None);
+
+        result.Should().BeSameAs(response);
+        VerifyLogError(Times.Never());
+    }
+
+    [Fact]
+    public async Task Handle_WhenHandlerThrows_RedactsSensitiveFieldsInLoggedPayload()
+    {
+        UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
+        TestRequest request = new("aaron", "hunter2");
+        RequestHandlerDelegate<TestResponse> next = () =>
+            throw new InvalidOperationException("boom");
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+        await act.Should().ThrowAsync<InvalidOperationException>();
+
+        string loggedMessage = CaptureLoggedMessage();
+        loggedMessage.Should().Contain("aaron").And.NotContain("hunter2");
+    }
+
+    private void VerifyLogError(Times times) =>
+        _loggerMock.Verify(
+            l =>
+                l.Log(
+                    LogLevel.Error,
+                    It.IsAny<EventId>(),
+                    It.IsAny<It.IsAnyType>(),
+                    It.IsAny<Exception>(),
+                    It.IsAny<Func<It.IsAnyType, Exception?, string>>()
+                ),
+            times
+        );
+
+    private string CaptureLoggedMessage()
+    {
+        var invocation = _loggerMock
+            .Invocations.Where(i => i.Method.Name == nameof(ILogger.Log))
+            .Should()
+            .ContainSingle()
+            .Subject;
+
+        object state = invocation.Arguments[2];
+        object? exception = invocation.Arguments[3];
+        object formatter = invocation.Arguments[4];
+        System.Reflection.MethodInfo invokeMethod = formatter.GetType().GetMethod("Invoke")!;
+
+        return (string)invokeMethod.Invoke(formatter, [state, exception])!;
+    }
+}
+
+public record TestRequest(string Username, string Password) : IRequest<TestResponse>;
+
+public record TestResponse(string Value);