Added more tests

Author: linkdotnet

src/LinkDotNet.Blog.Web/Features/Home/Index.razor

@@ -27,7 +27,7 @@
     <div class="content px-4 my-2">
     @for (var i = 0; i < currentPage.Count; i++)
     {
-        <ShortBlogPost BlogPost="currentPage[i]" UseAlternativeStyle="@(i % 2 != 0)"></ShortBlogPost>
+        <ShortBlogPost BlogPost="currentPage[i]" UseAlternativeStyle="@(i % 2 != 0)" LazyLoadPreviewImage="i > 3"></ShortBlogPost>
     }
     </div>
     <BlogPostNavigation PageList="@currentPage"></BlogPostNavigation>

tests/LinkDotNet.Blog.UnitTests/Web/Features/Components/PreviewImageTests.cs

@@ -0,0 +1,71 @@
+using System.Linq;
+using AngleSharp.Dom;
+using AngleSharp.Html.Dom;
+using AngleSharpWrappers;
+using Bunit;
+using LinkDotNet.Blog.Web.Features.Components;
+
+namespace LinkDotNet.Blog.UnitTests.Web.Features.Components;
+
+public class PreviewImageTests : TestContext
+{
+    [Fact]
+    public void ShouldOfferImageWhenProvided()
+    {
+        var cut = RenderComponent<PreviewImage>(ps => ps
+            .Add(p => p.PreviewImageUrl, "http://image.png/")
+            .Add(p => p.PreviewImageUrlFallback, "http://fallback.png/"));
+
+        var picture = cut.Find("picture");
+
+        var source = picture.Children[0] as IHtmlSourceElement;
+        source.Should().NotBeNull();
+        source.SourceSet.Should().Be("http://image.png/");
+        var img = picture.Children[1] as IHtmlImageElement;
+        img.Should().NotBeNull();
+        img.Source.Should().Be("http://fallback.png/");
+    }
+
+    [Fact]
+    public void ShouldOfferOnlyImageWhenNoFallbackProvided()
+    {
+        var cut = RenderComponent<PreviewImage>(ps => ps
+            .Add(p => p.PreviewImageUrl, "http://image.png/"));
+
+        var image = cut.Find("img").Unwrap() as IHtmlImageElement;
+
+        image.Should().NotBeNull();
+        image.Source.Should().Be("http://image.png/");
+    }
+
+    [Theory]
+    [InlineData(true, "lazy")]
+    [InlineData(false, "eager")]
+    public void ShouldSetLazyLoadBehavior(bool lazyLoad, string expectedLazy)
+    {
+        var cut = RenderComponent<PreviewImage>(ps => ps
+            .Add(p => p.PreviewImageUrl, "http://image.png/")
+            .Add(p => p.PreviewImageUrlFallback, "http://fallback.png/")
+            .Add(p => p.LazyLoadImage, lazyLoad));
+
+        var picture = cut.Find("picture");
+
+        var img = picture.Children[1] as IHtmlImageElement;
+        img.Should().NotBeNull();
+        img.Attributes.FirstOrDefault(a => a.Name == "loading").Value.Should().Be(expectedLazy);
+    }
+
+    [Theory]
+    [InlineData(true, "lazy")]
+    [InlineData(false, "eager")]
+    public void ShouldSetLazyLoadBehaviorNoFallback(bool lazyLoad, string expectedLazy)
+    {
+        var cut = RenderComponent<PreviewImage>(ps => ps
+            .Add(p => p.PreviewImageUrl, "http://image.png/")
+            .Add(p => p.LazyLoadImage, lazyLoad));
+
+        var image = cut.Find("img").Unwrap() as IHtmlImageElement;
+
+        image.Attributes.FirstOrDefault(a => a.Name == "loading").Value.Should().Be(expectedLazy);
+    }
+}