Fix language sorting in settings (#27158)

spec/helpers/languages_helper_spec.rb

@@ -60,4 +60,30 @@ describe LanguagesHelper do
       end
     end
   end
+
+  describe 'sorted_locales' do
+    context 'when sorting with native name' do
+      it 'returns Suomi after Gàidhlig' do
+        expect(described_class.sorted_locale_keys(%w(fi gd))).to eq(%w(gd fi))
+      end
+    end
+
+    context 'when sorting with diacritics' do
+      it 'returns Íslensk before Suomi' do
+        expect(described_class.sorted_locale_keys(%w(fi is))).to eq(%w(is fi))
+      end
+    end
+
+    context 'when sorting with non-Latin' do
+      it 'returns Suomi before Amharic' do
+        expect(described_class.sorted_locale_keys(%w(am fi))).to eq(%w(fi am))
+      end
+    end
+
+    context 'when sorting with local variants' do
+      it 'returns variant in-line' do
+        expect(described_class.sorted_locale_keys(%w(en eo en-GB))).to eq(%w(en en-GB eo))
+      end
+    end
+  end
 end