Don't update blogpost when same reference

Author: linkdotnet

src/LinkDotNet.Blog.Domain/BlogPost.cs

@@ -51,6 +51,11 @@ public static BlogPost Create(
 
     public void Update(BlogPost from)
     {
+        if (from == this)
+        {
+            return;
+        }
+
         Title = from.Title;
         ShortDescription = from.ShortDescription;
         Content = from.Content;
@@ -75,4 +80,4 @@ private void ReplaceTags(IEnumerable<Tag> tags)
             }
         }
     }
-}
+}

tests/LinkDotNet.Blog.UnitTests/Domain/BlogPostTests.cs

@@ -59,4 +59,15 @@ public void ShouldSetDateWhenGiven()
 
         blog.UpdatedDate.Should().Be(somewhen);
     }
-}
+
+    [Fact]
+    public void ShouldNotDeleteTagsWhenSameReference()
+    {
+        var bp = new BlogPostBuilder().WithTags("tag 1").Build();
+
+        bp.Update(bp);
+
+        bp.Tags.Should().HaveCount(1);
+        bp.Tags.Single().Content.Should().Be("tag 1");
+    }
+}