Deprecate PowerConverter based to_sipity_agent

app/conversions/power_converters/sipity_agent.rb

@@ -1,4 +1,6 @@
 PowerConverter.define_conversion_for(:sipity_agent) do |input|
+  Deprecation.warn('PowerConverter is deprecated. Use `Sipity::Agent(input)` instead')
+
   case input
   when Sipity::Agent
     input

app/forms/hyrax/forms/permission_template_form.rb

@@ -149,7 +149,7 @@ def agents_from_attributes
                     else
                       Hyrax::Group.new(grant[:agent_id])
                     end
-            PowerConverter.convert_to_sipity_agent(agent)
+            Sipity::Agent(agent)
           end
         end
 

app/models/hyrax/workflow_action_info.rb

@@ -5,7 +5,7 @@ def initialize(work, user)
       @work = work
       @user = user
       @entity = Sipity::Entity(work)
-      @agent = PowerConverter.convert(user, to: :sipity_agent)
+      @agent = Sipity::Agent(user)
     end
 
     attr_reader :entity, :agent, :user, :work

app/models/sipity.rb

@@ -1,6 +1,18 @@
 # frozen_string_literal: true
 
 module Sipity
+  ##
+  # Cast an object to an Entity
+  def Agent(input, &block) # rubocop:disable Naming/MethodName
+    result = case input
+             when Sipity::Agent
+               input
+             end
+
+    handle_conversion(input, result, :to_sipity_agent, &block)
+  end
+  module_function :Agent
+
   ##
   # Cast an object to an Entity
   def Entity(input, &block) # rubocop:disable Naming/MethodName

app/services/hyrax/workflow/permission_generator.rb

@@ -55,7 +55,7 @@ def initialize(roles:, workflow:, agents: [], **keywords)
         attr_reader :entity, :agents, :action_names, :roles
 
         def agents=(input)
-          @agents = Array.wrap(input).map { |agent| PowerConverter.convert_to_sipity_agent(agent) }
+          @agents = Array.wrap(input).map { |agent| Sipity::Agent(agent) }
         end
 
         def action_names=(input)

app/services/hyrax/workflow/permission_query.rb

@@ -163,9 +163,9 @@ def authorized_for_processing?(user:, entity:, action:)
       def scope_processing_agents_for(user:)
         return Sipity::Agent.none if user.blank?
         return Sipity::Agent.none unless user.persisted?
-        user_agent = PowerConverter.convert_to_sipity_agent(user)
+        user_agent = Sipity::Agent(user)
         group_agents = user.groups.map do |g|
-          PowerConverter.convert_to_sipity_agent(Hyrax::Group.new(g))
+          Sipity::Agent(Hyrax::Group.new(g))
         end
         Sipity::Agent.where(id: group_agents + [user_agent])
       end

spec/models/sipity_spec.rb

@@ -1,4 +1,21 @@
 RSpec.describe Sipity do
+  describe '.Agent' do
+    it 'will convert a Sipity::Agent' do
+      object = Sipity::Agent.new
+      expect(described_class.Agent(object)).to eq(object)
+    end
+
+    it 'will convert an object that responds to #to_sipity_agent' do
+      object = double(to_sipity_agent: :a_sipity_agent)
+      expect(described_class.Agent(object)).to eq(:a_sipity_agent)
+    end
+
+    it 'will raise an exception if it cannot convert the given object' do
+      expect { described_class.Agent(double) }
+        .to raise_error(PowerConverter::ConversionError)
+    end
+  end
+
   describe '.Entity' do
     context "with a Sipity::Entity" do
       let(:object) { Sipity::Entity.new }