Fixed bug where tags where added multiple times

Author: linkdotnet

LinkDotNet.Blog.Domain/BlogPost.cs

@@ -57,7 +57,23 @@ public void Update(BlogPost from)
             UpdatedDate = from.UpdatedDate;
             PreviewImageUrl = from.PreviewImageUrl;
             IsPublished = from.IsPublished;
-            Tags = from.Tags;
+            ReplaceTags(from.Tags);
+        }
+
+        private void ReplaceTags(IEnumerable<Tag> tags)
+        {
+            Tags?.Clear();
+            if (Tags == null || tags == null)
+            {
+                Tags = tags?.ToList();
+            }
+            else
+            {
+                foreach (var tag in tags)
+                {
+                    Tags.Add(tag);
+                }
+            }
         }
     }
 }

LinkDotNet.Blog.UnitTests/Domain/BlogPostTests.cs

@@ -27,6 +27,20 @@ public void ShouldUpdateBlogPost()
             blogPostToUpdate.Tags.Should().BeNullOrEmpty();
         }
 
+        [Fact]
+        public void ShouldUpdateTagsWhenExisting()
+        {
+            var blogPostToUpdate = new BlogPostBuilder().WithTags("tag 1").Build();
+            blogPostToUpdate.Id = "random-id";
+            var blogPost = new BlogPostBuilder().WithTags("tag 2").Build();
+            blogPost.Id = "something else";
+
+            blogPostToUpdate.Update(blogPost);
+
+            blogPostToUpdate.Tags.Should().HaveCount(1);
+            blogPostToUpdate.Tags.Single().Content.Should().Be("tag 2");
+        }
+
         [Fact]
         public void ShouldTrimWhitespacesFromTags()
         {

LinkDotNet.Blog.Web/Program.cs

@@ -3,7 +3,7 @@
 
 namespace LinkDotNet.Blog.Web
 {
-    public class Program
+    public static class Program
     {
         public static void Main(string[] args)
         {