Make sanitizer *not* add no-referrer etc. in local markdown toots if the link is “safe”

spec/lib/sanitize_config_spec.rb

@@ -7,6 +7,12 @@ describe Sanitize::Config do
   describe '::MASTODON_STRICT' do
     subject { Sanitize::Config::MASTODON_STRICT }
 
+    around do |example|
+      original_web_domain = Rails.configuration.x.web_domain
+      example.run
+      Rails.configuration.x.web_domain = original_web_domain
+    end
+
     it 'keeps h1' do
       expect(Sanitize.fragment('<h1>Foo</h1>', subject)).to eq '<h1>Foo</h1>'
     end
@@ -32,7 +38,12 @@ describe Sanitize::Config do
     end
 
     it 'keeps a with href and rel tag' do
-      expect(Sanitize.fragment('<a href="http://example.com" rel="tag">Test</a>', subject)).to eq '<a href="http://example.com" rel="nofollow noopener noreferrer tag" target="_blank">Test</a>'
+      expect(Sanitize.fragment('<a href="http://example.com" rel="tag">Test</a>', subject)).to eq '<a href="http://example.com" rel="tag nofollow noopener noreferrer" target="_blank">Test</a>'
+    end
+
+    it 'keeps a with href and rel tag, not adding to rel if url is local' do
+      Rails.configuration.x.web_domain = 'domain.test'
+      expect(Sanitize.fragment('<a href="http://domain.test/tags/foo" rel="tag">Test</a>', subject.merge(outgoing: true))).to eq '<a href="http://domain.test/tags/foo" rel="tag" target="_blank">Test</a>'
     end
   end
 end