FIX: Check for group name availability should skip reserved usernames.

spec/services/username_checker_service_spec.rb

@@ -15,6 +15,7 @@ describe UsernameCheckerService do
         result = @service.check_username('a', @nil_email)
         expect(result).to have_key(:errors)
       end
+
       it 'rejects too long usernames' do
         result = @service.check_username('a123456789b123456789c123456789', @nil_email)
         expect(result).to have_key(:errors)
@@ -29,6 +30,23 @@ describe UsernameCheckerService do
         result = @service.check_username('.vincent', @nil_email)
         expect(result).to have_key(:errors)
       end
+
+      describe 'reserved usernames' do
+        before do
+          SiteSetting.reserved_usernames = 'test|donkey'
+        end
+
+        it 'rejects usernames that are reserved' do
+          result = @service.check_username("test", @nil_email)
+          expect(result[:available]).to eq(false)
+        end
+
+        it 'allows reserved username checker to be skipped' do
+          @service = UsernameCheckerService.new(allow_reserved_username: true)
+          result = @service.check_username("test", @nil_email)
+          expect(result[:available]).to eq(true)
+        end
+      end
     end
 
     it 'username not available locally' do