[Feat] Implement Endpoint for Updating a Comment on a Blog

src/Hng.Application.Test/Features/Comment/UpdateCommentCommandShould.cs

@@ -0,0 +1,192 @@
+using System.Linq.Expressions;
+using AutoMapper;
+using Hng.Application.Features.Comments.Commands;
+using Hng.Application.Features.Comments.Dtos;
+using Hng.Application.Features.Comments.Handlers;
+using Hng.Domain.Entities;
+using Hng.Infrastructure.Repository.Interface;
+using Hng.Infrastructure.Services.Interfaces;
+using Moq;
+using Xunit;
+
+public class UpdateCommentCommandShould
+{
+    private readonly IMapper _mapper;
+    private readonly Mock<IRepository<Comment>> _commentRepositoryMock;
+    private readonly Mock<IAuthenticationService> _authenticationServiceMock;
+    private readonly UpdateCommentCommandHandler _handler;
+
+    public UpdateCommentCommandShould()
+    {
+        // Setup AutoMapper
+        var configuration = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<UpdateCommentDto, Comment>().ReverseMap();
+            cfg.CreateMap<Comment, CommentDto>().ReverseMap();
+        });
+        _mapper = configuration.CreateMapper();
+
+        _commentRepositoryMock = new Mock<IRepository<Comment>>();
+        _authenticationServiceMock = new Mock<IAuthenticationService>();
+        _handler = new UpdateCommentCommandHandler(
+            _mapper,
+            _commentRepositoryMock.Object,
+            _authenticationServiceMock.Object
+        );
+    }
+
+    [Fact]
+    public async Task Handle_ShouldUpdateCommentSuccessfully()
+    {
+        // Arrange
+        var blogId = Guid.NewGuid();
+        var commentId = Guid.NewGuid();
+        var userId = Guid.NewGuid();
+        var updateCommentDto = new UpdateCommentDto { Content = "Updated content" };
+        var comment = new Comment
+        {
+            Id = commentId,
+            BlogId = blogId,
+            AuthorId = userId,
+            Content = "Original content",
+            CreatedAt = DateTime.UtcNow
+        };
+
+        _commentRepositoryMock
+            .Setup(r => r.GetBySpec(It.IsAny<Expression<Func<Comment, bool>>>()))
+            .ReturnsAsync(comment);
+
+        _authenticationServiceMock
+            .Setup(s => s.GetCurrentUserAsync())
+            .ReturnsAsync(userId);
+
+        _commentRepositoryMock
+            .Setup(r => r.UpdateAsync(It.IsAny<Comment>()))
+            .Returns(Task.CompletedTask);
+
+        _commentRepositoryMock
+            .Setup(r => r.SaveChanges())
+            .Returns(Task.CompletedTask);
+
+        // Act
+        var result = await _handler.Handle(
+            new UpdateCommentCommand(blogId, commentId, updateCommentDto, userId),
+            CancellationToken.None
+        );
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(200, result.StatusCode);
+        Assert.Equal("Comment updated successfully", result.Message);
+        Assert.Equal("Updated content", result.Data.Content);
+        _commentRepositoryMock.Verify(r => r.UpdateAsync(It.IsAny<Comment>()), Times.Once);
+        _commentRepositoryMock.Verify(r => r.SaveChanges(), Times.Once);
+    }
+
+    [Fact]
+    public async Task Handle_ShouldReturnNotFound_WhenCommentNotFound()
+    {
+        // Arrange
+        var blogId = Guid.NewGuid();
+        var commentId = Guid.NewGuid();
+        var userId = Guid.NewGuid();
+        var updateCommentDto = new UpdateCommentDto { Content = "Updated content" };
+
+        _commentRepositoryMock
+            .Setup(r => r.GetBySpec(It.IsAny<Expression<Func<Comment, bool>>>()))
+            .ReturnsAsync((Comment)null);
+
+        _authenticationServiceMock
+            .Setup(s => s.GetCurrentUserAsync())
+            .ReturnsAsync(userId);
+
+        // Act
+        var result = await _handler.Handle(
+            new UpdateCommentCommand(blogId, commentId, updateCommentDto, userId),
+            CancellationToken.None
+        );
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(404, result.StatusCode);
+        Assert.Equal("Comment not found.", result.Message);
+        Assert.Null(result.Data);
+    }
+
+    [Fact]
+    public async Task Handle_ShouldReturnUnauthorized_WhenUserIsNotAuthorized()
+    {
+        // Arrange
+        var blogId = Guid.NewGuid();
+        var commentId = Guid.NewGuid();
+        var userId = Guid.NewGuid();
+        var anotherUserId = Guid.NewGuid();
+        var updateCommentDto = new UpdateCommentDto { Content = "Updated content" };
+        var comment = new Comment
+        {
+            Id = commentId,
+            BlogId = blogId,
+            AuthorId = userId,
+            Content = "Original content",
+            CreatedAt = DateTime.UtcNow
+        };
+
+        _commentRepositoryMock
+            .Setup(r => r.GetBySpec(It.IsAny<Expression<Func<Comment, bool>>>()))
+            .ReturnsAsync(comment);
+
+        _authenticationServiceMock
+            .Setup(s => s.GetCurrentUserAsync())
+            .ReturnsAsync(anotherUserId);
+
+        // Act
+        var result = await _handler.Handle(
+            new UpdateCommentCommand(blogId, commentId, updateCommentDto, anotherUserId),
+            CancellationToken.None
+        );
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(403, result.StatusCode);
+        Assert.Equal("You are not authorized to update this comment.", result.Message);
+        Assert.Null(result.Data);
+    }
+
+    [Fact]
+    public async Task Handle_ShouldReturnBadRequest_WhenContentIsEmpty()
+    {
+        // Arrange
+        var blogId = Guid.NewGuid();
+        var commentId = Guid.NewGuid();
+        var userId = Guid.NewGuid();
+        var updateCommentDto = new UpdateCommentDto { Content = string.Empty };
+        var comment = new Comment
+        {
+            Id = commentId,
+            BlogId = blogId,
+            AuthorId = userId,
+            Content = "Original content",
+            CreatedAt = DateTime.UtcNow
+        };
+
+        _commentRepositoryMock
+            .Setup(r => r.GetBySpec(It.IsAny<Expression<Func<Comment, bool>>>()))
+            .ReturnsAsync(comment);
+
+        _authenticationServiceMock
+            .Setup(s => s.GetCurrentUserAsync())
+            .ReturnsAsync(userId);
+
+        // Act
+        var result = await _handler.Handle(
+            new UpdateCommentCommand(blogId, commentId, updateCommentDto, userId),
+            CancellationToken.None
+        );
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(400, result.StatusCode);
+        Assert.Equal("Comment cannot be empty.", result.Message);
+        Assert.Null(result.Data);
+    }
+}

src/Hng.Application/Features/Comments/Commands/UpdateCommentCommand.cs

@@ -0,0 +1,14 @@
+using Hng.Application.Features.Comments.Dtos;
+using Hng.Application.Shared.Dtos;
+using MediatR;
+
+namespace Hng.Application.Features.Comments.Commands
+{
+    public class UpdateCommentCommand(Guid blogId, Guid commentId, UpdateCommentDto body, Guid userId) : IRequest<SuccessResponseDto<CommentDto>>
+    {
+        public Guid BlogId { get; } = blogId;
+        public Guid commentId { get; } = commentId;
+        public UpdateCommentDto CommentBody { get; } = body;
+        public Guid userId { get; } = userId;
+    }
+}

src/Hng.Application/Features/Comments/Dtos/UpdateCommentDto.cs

@@ -0,0 +1,10 @@
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace Hng.Application.Features.Comments.Dtos;
+
+public class UpdateCommentDto
+{
+    [JsonPropertyName("content")]
+    public string Content { get; set; } = string.Empty;
+}

src/Hng.Application/Features/Comments/Handlers/UpdateCommentCommandHandler.cs

@@ -0,0 +1,70 @@
+using AutoMapper;
+using Hng.Application.Features.Comments.Commands;
+using Hng.Application.Features.Comments.Dtos;
+using Hng.Application.Shared.Dtos;
+using Hng.Domain.Entities;
+using Hng.Infrastructure.Repository.Interface;
+using Hng.Infrastructure.Services.Interfaces;
+using MediatR;
+
+namespace Hng.Application.Features.Comments.Handlers;
+
+public class UpdateCommentCommandHandler(
+    IMapper mapper,
+    IRepository<Comment> commentRepository,
+    IAuthenticationService authenticationService)
+    : IRequestHandler<UpdateCommentCommand, SuccessResponseDto<CommentDto>>
+{
+    private readonly IMapper _mapper = mapper;
+    private readonly IRepository<Comment> _commentRepository = commentRepository;
+    private readonly IAuthenticationService _authenticationService = authenticationService;
+
+    public async Task<SuccessResponseDto<CommentDto>> Handle(UpdateCommentCommand request, CancellationToken cancellationToken)
+    {
+        var comment = await _commentRepository.GetBySpec(c => c.Id == request.commentId && c.BlogId == request.BlogId);
+        if (comment == null)
+        {
+            return new SuccessResponseDto<CommentDto>
+            {
+                Data = null,
+                Message = "Comment not found.",
+                StatusCode = 404
+            };
+        }
+
+        var userId = await _authenticationService.GetCurrentUserAsync();
+        if (comment.AuthorId != userId)
+        {
+            return new SuccessResponseDto<CommentDto>
+            {
+                Data = null,
+                Message = "You are not authorized to update this comment.",
+                StatusCode = 403
+            };
+        }
+
+        if (string.IsNullOrWhiteSpace(request.CommentBody.Content))
+        {
+            return new SuccessResponseDto<CommentDto>
+            {
+                Data = null,
+                Message = "Comment cannot be empty.",
+                StatusCode = 400
+            };
+        }
+
+        // Update only the content field
+        comment.Content = request.CommentBody.Content;
+        comment.UpdatedAt = DateTime.UtcNow;
+
+        await _commentRepository.UpdateAsync(comment);
+        await _commentRepository.SaveChanges();
+
+        return new SuccessResponseDto<CommentDto>
+        {
+            Data = _mapper.Map<CommentDto>(comment),
+            Message = "Comment updated successfully",
+            StatusCode = 200
+        };
+    }
+}

src/Hng.Application/Features/Comments/Mappers/CommentMapperProfile.cs

@@ -9,6 +9,7 @@ public class CommentMapperProfile : Profile
     public CommentMapperProfile()
     {
         CreateMap<CreateCommentDto, Comment>();
+        CreateMap<UpdateCommentDto, Comment>();
         CreateMap<Comment, CommentDto>()
             .ReverseMap();
     }

src/Hng.Domain/Entities/Comment.cs

@@ -12,4 +12,5 @@ public class Comment : EntityBase
     public User Author { get; set; }
 
     public DateTime CreatedAt { get; set; }
+    public DateTime? UpdatedAt { get; set; }
 }