diff --git a/test/unit/post_test.rb b/test/unit/post_test.rb
index 42deb0b7f..bd58894a0 100644
--- a/test/unit/post_test.rb
+++ b/test/unit/post_test.rb
@@ -1546,6 +1546,42 @@ class PostTest < ActiveSupport::TestCase
           assert_equal("http://www.hentai-foundry.com/pictures/user/AnimeFlux/219123", @post.normalized_source)
         end
       end
+
+      context "when validating tags" do
+        should "warn when creating a new general tag" do
+          @post.add_tag("tag")
+          @post.save
+
+          assert_match(/Created 1 new tag: \[\[tag\]\]/, @post.warnings.full_messages.join)
+        end
+
+        should "warn when adding an artist tag without an artist entry" do
+          @post.add_tag("artist:bkub")
+          @post.save
+
+          assert_match(/Artist \[\[bkub\]\] requires an artist entry./, @post.warnings.full_messages.join)
+        end
+
+        should "warn when a tag removal failed due to implications or automatic tags" do
+          ti = FactoryGirl.create(:tag_implication, antecedent_name: "cat", consequent_name: "animal")
+          @post.reload
+          @post.update(old_tag_string: @post.tag_string, tag_string: "chen_(cosplay) chen cosplay cat animal")
+          @post.reload
+          @post.update(old_tag_string: @post.tag_string, tag_string: "chen_(cosplay) chen cosplay cat -cosplay")
+
+          assert_match(/\[\[animal\]\] and \[\[cosplay\]\] could not be removed./, @post.warnings.full_messages.join)
+        end
+
+        should "warn when a post from a known source is missing an artist tag" do
+          post = FactoryGirl.build(:post, source: "https://www.pixiv.net/member_illust.php?mode=medium&illust_id=65985331")
+          post.save
+          assert_match(/Artist tag is required/, post.warnings.full_messages.join)
+        end
+
+        should "warn when missing a copyright tag" do
+          assert_match(/Copyright tag is required/, @post.warnings.full_messages.join)
+        end
+      end
     end
   end