feat: Show error page when no blog post was foumd

src/LinkDotNet.Blog.Web/Features/ShowBlogPost/ShowBlogPostPage.razor

@@ -10,10 +10,19 @@
 @inject IOptions<ApplicationConfiguration> AppConfiguration
 @inject IOptions<ProfileInformation> ProfileInformation
 
-@if (BlogPost is null)
+@if (isLoading)
 {
     <Loading></Loading>
 }
+else if (!isLoading && BlogPost is null)
+{
+	<div class="m-auto text-center" id="no-blog-post-error">
+		<h1 class="fs-1">404 - o((⊙﹏⊙))o</h1>
+		<br/>
+		<p>I really looked hard but I couldn't find the page you are looking for.</p>
+		<p>Go back to <a href="/">safety</a></p>
+	</div>
+}
 else
 {
     <PageTitle>@BlogPost.Title</PageTitle>
@@ -77,14 +86,18 @@ else
     [Parameter]
     public string Slug { get; set; }
 
+    private bool isLoading;
+
 	private string OgDataImage => BlogPost.PreviewImageUrlFallback ?? BlogPost.PreviewImageUrl;
 	private string BlogPostCanoncialUrl => $"blogPost/{BlogPost.Id}";
 
     private BlogPost BlogPost { get; set; }
 
     protected override async Task OnParametersSetAsync()
     {
+	    isLoading = true;
         BlogPost = await BlogPostRepository.GetByIdAsync(BlogPostId);
+        isLoading = false;
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)

tests/LinkDotNet.Blog.IntegrationTests/Web/Features/ShowBlogPost/ShowBlogPostPageTests.cs

@@ -101,6 +101,19 @@ public async Task ShouldSetStructuredData()
         structuredData.Instance.PreviewFallbackImage.Should().Be("image2");
     }
 
+    [Fact]
+    public void ShouldShowErrorPageWhenBlogPostNotFound()
+    {
+        using var ctx = new TestContext();
+        ctx.JSInterop.Mode = JSRuntimeMode.Loose;
+        RegisterComponents(ctx);
+
+        var cut = ctx.RenderComponent<ShowBlogPostPage>();
+
+        cut.FindAll(".blogpost-content").Should().HaveCount(0);
+        cut.FindAll("#no-blog-post-error").Should().HaveCount(1);
+    }
+
     private void RegisterComponents(TestContextBase ctx, ILocalStorageService localStorageService = null)
     {
         ctx.Services.AddScoped(_ => Repository);