Show what protocol is used for accounts in admin/accounts#index (#4622)

* Show what protocol used for in admin/accounts#index

* Add frozen_string_literal

spec/helpers/account_helper_spec.rb

@@ -0,0 +1,30 @@
+require 'rails_helper'
+
+# Specs in this file have access to a helper object that includes
+# the AccountHelper. For example:
+#
+# describe AccountHelper do
+#   describe "string concat" do
+#     it "concats two strings with spaces" do
+#       expect(helper.concat_strings("this","that")).to eq("this that")
+#     end
+#   end
+# end
+RSpec.describe AccountHelper, type: :helper do
+  describe '#protocol_for_display' do
+    it "returns OStatus when the protocol is 'ostatus'" do
+      protocol = 'ostatus'
+      expect(protocol_for_display(protocol)).to eq 'OStatus'
+    end
+
+    it "returns ActivityPub when the protocol is 'activitypub'" do
+      protocol = 'activitypub'
+      expect(protocol_for_display(protocol)).to eq 'ActivityPub'
+    end
+
+    it "returns the same string when the protocol is unknown" do
+      protocol = 'wave'
+      expect(protocol_for_display(protocol)).to eq protocol
+    end
+  end
+end