Fix CA1873 warning and consolidate test fixtures (#313)

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

@@ -0,0 +1,9 @@
+using MediatR;
+
+namespace Shared.Application.Tests.Behaviors;
+
+// ReSharper disable NotAccessedPositionalProperty.Global
+public sealed record TestRequest(string Username, string Password) : IRequest<TestResponse>;
+
+public sealed record TestResponse(string Value);
+// ReSharper restore NotAccessedPositionalProperty.Global

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

@@ -14,15 +14,18 @@ public class UnhandledExceptionLoggingBehaviorTests
         ILogger<UnhandledExceptionLoggingBehavior<TestRequest, TestResponse>>
     > _loggerMock = new();
 
-    private UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> CreateBehavior() =>
+    private UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> CreateBehavior()
-        new(_loggerMock.Object);
+    {
+        _loggerMock.Setup(l => l.IsEnabled(LogLevel.Error)).Returns(true);
+        return new(_loggerMock.Object);
+    }
 
     [Fact]
     public async Task Handle_WhenHandlerThrowsGenericException_LogsOnceAndRethrows()
     {
         UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
-        TestRequest request = new("aaron", "hunter2");
+        TestRequest request = new("aaron", "pa$$word123");
-        InvalidOperationException thrown = new("boom");
+        InvalidOperationException thrown = new("Something went wrong.");
         RequestHandlerDelegate<TestResponse> next = () => throw thrown;
 
         Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
@@ -37,7 +40,7 @@ public class UnhandledExceptionLoggingBehaviorTests
     public async Task Handle_WhenValidationExceptionThrown_DoesNotLogAndRethrows()
     {
         UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
-        TestRequest request = new("aaron", "hunter2");
+        TestRequest request = new("aaron", "pa$$word123");
         ValidationException thrown = new([new ValidationFailure("Username", "is required")]);
         RequestHandlerDelegate<TestResponse> next = () => throw thrown;
 
@@ -51,7 +54,7 @@ public class UnhandledExceptionLoggingBehaviorTests
     public async Task Handle_WhenHandlerSucceeds_DoesNotLogAndReturnsResponse()
     {
         UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
-        TestRequest request = new("aaron", "hunter2");
+        TestRequest request = new("aaron", "pa$$word123");
         TestResponse response = new("ok");
         RequestHandlerDelegate<TestResponse> next = () => Task.FromResult(response);
 
@@ -65,15 +68,15 @@ public class UnhandledExceptionLoggingBehaviorTests
     public async Task Handle_WhenHandlerThrows_RedactsSensitiveFieldsInLoggedPayload()
     {
         UnhandledExceptionLoggingBehavior<TestRequest, TestResponse> behavior = CreateBehavior();
-        TestRequest request = new("aaron", "hunter2");
+        TestRequest request = new("aaron", "pa$$word123");
         RequestHandlerDelegate<TestResponse> next = () =>
-            throw new InvalidOperationException("boom");
+            throw new InvalidOperationException("Something went wrong.");
 
         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");
+        loggedMessage.Should().Contain("aaron").And.NotContain("pa$$word123");
     }
 
     private void VerifyLogError(Times times) =>
@@ -91,21 +94,17 @@ public class UnhandledExceptionLoggingBehaviorTests
 
     private string CaptureLoggedMessage()
     {
-        var invocation = _loggerMock
+        IInvocation? 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 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);

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

@@ -0,0 +1,188 @@
+using FluentAssertions;
+using FluentValidation;
+using FluentValidation.Results;
+using MediatR;
+using Moq;
+using Shared.Application.Behaviors;
+
+namespace Shared.Application.Tests.Behaviors;
+
+public class ValidationBehaviorTests
+{
+    private static ValidationBehavior<TestRequest, TestResponse> CreateBehavior(
+        params IValidator<TestRequest>[] validators
+    ) => new(validators);
+
+    [Fact]
+    public async Task Handle_WhenRequestPassesAllValidators_InvokesNextUnchanged()
+    {
+        Mock<IValidator<TestRequest>> validatorMock = new();
+        validatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult());
+        ValidationBehavior<TestRequest, TestResponse> behavior = CreateBehavior(
+            validatorMock.Object
+        );
+        TestRequest request = new("aaron", "pa$$word123");
+        TestResponse response = new("ok");
+        bool nextInvoked = false;
+        RequestHandlerDelegate<TestResponse> next = () =>
+        {
+            nextInvoked = true;
+            return Task.FromResult(response);
+        };
+
+        TestResponse result = await behavior.Handle(
+            request,
+            next,
+            CancellationToken.None
+        );
+
+        nextInvoked.Should().BeTrue();
+        result.Should().BeSameAs(response);
+    }
+
+    [Fact]
+    public async Task Handle_WhenValidatorReportsFailures_ThrowsValidationExceptionAndNeverInvokesNext()
+    {
+        ValidationFailure failure = new("Username", "is required");
+        Mock<IValidator<TestRequest>> validatorMock = new();
+        validatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult([failure]));
+        ValidationBehavior<TestRequest, TestResponse> behavior = CreateBehavior(
+            validatorMock.Object
+        );
+        TestRequest request = new("", "pa$$word123");
+        bool nextInvoked = false;
+        RequestHandlerDelegate<TestResponse> next = () =>
+        {
+            nextInvoked = true;
+            return Task.FromResult(new TestResponse("ok"));
+        };
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<ValidationException>())
+            .Which.Errors.Should()
+            .ContainSingle()
+            .Which.Should()
+            .BeSameAs(failure);
+        nextInvoked.Should().BeFalse();
+    }
+
+    [Fact]
+    public async Task Handle_WhenMultipleValidatorsAreRegistered_RunsAllOfThem()
+    {
+        Mock<IValidator<TestRequest>> firstValidatorMock = new();
+        firstValidatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult());
+        Mock<IValidator<TestRequest>> secondValidatorMock = new();
+        secondValidatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult());
+        ValidationBehavior<TestRequest, TestResponse> behavior = CreateBehavior(
+            firstValidatorMock.Object,
+            secondValidatorMock.Object
+        );
+        TestRequest request = new("aaron", "pa$$word123");
+        RequestHandlerDelegate<TestResponse> next = () =>
+            Task.FromResult(new TestResponse("ok"));
+
+        await behavior.Handle(request, next, CancellationToken.None);
+
+        firstValidatorMock.Verify(
+            v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                ),
+            Times.Once()
+        );
+        secondValidatorMock.Verify(
+            v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                ),
+            Times.Once()
+        );
+    }
+
+    [Fact]
+    public async Task Handle_WhenMultipleValidatorsReportFailures_AggregatesErrorsFromAll()
+    {
+        ValidationFailure firstFailure = new("Username", "is required");
+        ValidationFailure secondFailure = new("Username", "must be at least 3 characters");
+        Mock<IValidator<TestRequest>> firstValidatorMock = new();
+        firstValidatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult([firstFailure]));
+        Mock<IValidator<TestRequest>> secondValidatorMock = new();
+        secondValidatorMock
+            .Setup(v =>
+                v.ValidateAsync(
+                    It.IsAny<ValidationContext<TestRequest>>(),
+                    It.IsAny<CancellationToken>()
+                )
+            )
+            .ReturnsAsync(new ValidationResult([secondFailure]));
+        ValidationBehavior<TestRequest, TestResponse> behavior = CreateBehavior(
+            firstValidatorMock.Object,
+            secondValidatorMock.Object
+        );
+        TestRequest request = new("", "pa$$word123");
+        RequestHandlerDelegate<TestResponse> next = () =>
+            Task.FromResult(new TestResponse("ok"));
+
+        Func<Task> act = async () => await behavior.Handle(request, next, CancellationToken.None);
+
+        (await act.Should().ThrowAsync<ValidationException>())
+            .Which.Errors.Should()
+            .BeEquivalentTo([firstFailure, secondFailure]);
+    }
+
+    [Fact]
+    public async Task Handle_WhenNoValidatorsAreRegistered_InvokesNext()
+    {
+        ValidationBehavior<TestRequest, TestResponse> behavior =
+            CreateBehavior();
+        TestRequest request = new("aaron", "pa$$word123");
+        TestResponse response = new("ok");
+        RequestHandlerDelegate<TestResponse> next = () => Task.FromResult(response);
+
+        TestResponse result = await behavior.Handle(
+            request,
+            next,
+            CancellationToken.None
+        );
+
+        result.Should().BeSameAs(response);
+    }
+}

web/backend/Shared/Shared.Application/Behaviors/UnhandledExceptionLoggingBehavior.cs

@@ -6,18 +6,11 @@ using Microsoft.Extensions.Logging;
 
 namespace Shared.Application.Behaviors;
 
-/// <summary>
+public abstract class JsonLogger
-///     MediatR pipeline behavior that logs unhandled exceptions together with the request type and
-///     payload, then rethrows them unchanged for <c>GlobalExceptionFilter</c> to map to a status code.
-/// </summary>
-public class UnhandledExceptionLoggingBehavior<TRequest, TResponse>(
-    ILogger<UnhandledExceptionLoggingBehavior<TRequest, TResponse>> logger
-) : IPipelineBehavior<TRequest, TResponse>
-    where TRequest : IRequest<TResponse>
 {
     private static readonly string[] SensitiveFieldNames = ["password", "token"];
 
-    private static readonly JsonSerializerOptions SerializerOptions = new()
+    protected static readonly JsonSerializerOptions SerializerOptions = new()
     {
         TypeInfoResolver = new DefaultJsonTypeInfoResolver
         {
@@ -25,46 +18,6 @@ public class UnhandledExceptionLoggingBehavior<TRequest, TResponse>(
         },
     };
 
-    /// <inheritdoc/>
-    public async Task<TResponse> Handle(
-        TRequest request,
-        RequestHandlerDelegate<TResponse> next,
-        CancellationToken cancellationToken
-    )
-    {
-        try
-        {
-            return await next();
-        }
-        catch (ValidationException)
-        {
-            // Expected: ValidationBehavior already reports these as request errors, not incidents.
-            throw;
-        }
-        catch (Exception ex)
-        {
-            logger.LogError(
-                ex,
-                "Unhandled exception while processing {RequestName}: {RequestPayload}",
-                typeof(TRequest).Name,
-                Serialize(request)
-            );
-            throw;
-        }
-    }
-
-    private static string Serialize(TRequest request)
-    {
-        try
-        {
-            return JsonSerializer.Serialize(request, SerializerOptions);
-        }
-        catch (Exception)
-        {
-            return "<unable to serialize request payload>";
-        }
-    }
-
     private static void RedactSensitiveProperties(JsonTypeInfo typeInfo)
     {
         if (typeInfo.Kind != JsonTypeInfoKind.Object)
@@ -84,3 +37,71 @@ public class UnhandledExceptionLoggingBehavior<TRequest, TResponse>(
         }
     }
 }
+
+/// <summary>
+///     MediatR pipeline behavior that logs unhandled exceptions together with the
+///     request type and
+///     payload, then rethrows them unchanged for <c>GlobalExceptionFilter</c> to
+///     map to a status code.
+/// </summary>
+public partial class UnhandledExceptionLoggingBehavior<TRequest, TResponse>
+    : JsonLogger,
+        IPipelineBehavior<TRequest, TResponse>
+    where TRequest : IRequest<TResponse>
+{
+    private readonly ILogger<UnhandledExceptionLoggingBehavior<TRequest, TResponse>> _logger;
+
+    public UnhandledExceptionLoggingBehavior(
+        ILogger<UnhandledExceptionLoggingBehavior<TRequest, TResponse>> logger
+    )
+    {
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public async Task<TResponse> Handle(
+        TRequest request,
+        RequestHandlerDelegate<TResponse> next,
+        CancellationToken cancellationToken
+    )
+    {
+        try
+        {
+            return await next();
+        }
+        catch (ValidationException)
+        {
+            // Expected: ValidationBehavior already reports these as request errors
+            throw;
+        }
+        catch (Exception ex)
+        {
+            if (_logger.IsEnabled(LogLevel.Error))
+                LogUnhandledException(ex, typeof(TRequest).Name, Serialize(request));
+            
+            throw;
+        }
+    }
+
+    private static string Serialize(TRequest request)
+    {
+        try
+        {
+            return JsonSerializer.Serialize(request, SerializerOptions);
+        }
+        catch (Exception)
+        {
+            return "<unable to serialize request payload>";
+        }
+    }
+
+    [LoggerMessage(
+        Level = LogLevel.Error,
+        Message = "Unhandled exception while processing {RequestName}: {RequestPayload}"
+    )]
+    private partial void LogUnhandledException(
+        Exception ex,
+        string requestName,
+        string requestPayload
+    );
+}

web/backend/Shared/Shared.Application/Behaviors/ValidationBehavior.cs

@@ -5,7 +5,8 @@ using MediatR;
 namespace Shared.Application.Behaviors;
 
 /// <summary>
-///     MediatR pipeline behavior that runs registered FluentValidation validators before the handler,
+///     MediatR pipeline behavior that runs registered FluentValidation validators
+///     before the handler,
 ///     throwing <see cref="ValidationException" /> if any report failures.
 /// </summary>
 public class ValidationBehavior<TRequest, TResponse>(IEnumerable<IValidator<TRequest>> validators)