convert parameter helper to a privacy level decorator

test plan: specs pass

fixes PLAT-2587

Change-Id: I92a73ea9f45447db09bace05721bcb81fe45ecde
Reviewed-on: https://gerrit.instructure.com/111698
Tested-by: Jenkins
Reviewed-by: Weston Dransfield <wdransfield@instructure.com>
Product-Review: Brad Humphrey <brad@instructure.com>
QA-Review: Brad Humphrey <brad@instructure.com>

app/controllers/external_tools_controller.rb

@@ -661,11 +661,14 @@ class ExternalToolsController < ApplicationController
     }
 
     collaboration = opts[:content_item_id].present? ? ExternalToolCollaboration.find(opts[:content_item_id]) : nil
-    params_helper = content_item_param_helper(placement, collaboration)
+    base_expander = variable_expander(tool: tool, collaboration: collaboration)
+    expander = Lti::PrivacyLevelExpander.new(placement, base_expander)
 
-    selection_request.generate_lti_launch(placement: placement,
-                                          expanded_variables: params_helper.expanded_variables,
-                                          opts: opts)
+    selection_request.generate_lti_launch(
+      placement: placement,
+      expanded_variables: expander.expanded_variables!(tool.set_custom_fields(placement)),
+      opts: opts
+    )
   end
   protected :content_item_selection_request
 
@@ -1085,19 +1088,6 @@ class ExternalToolsController < ApplicationController
     Lti::VariableExpander.new(@domain_root_account, @context, self, default_opts.merge(opts))
   end
 
-  def content_item_param_helper(placement, collaboration)
-    Lti::PrivacyLevelExpander.new(tool: @tool,
-                                        placement: placement,
-                                        collaboration: collaboration,
-                                        context: @context,
-                                        opts: {
-                                          current_user: @current_user,
-                                          current_pseudonym: @current_pseudonym,
-                                          domain_root_account: @domain_root_account,
-                                          controller: self
-                                        })
-  end
-
   def placement_from_params
     params[:placement] || params[:launch_type] || "#{@context.class.base_class.to_s.downcase}_navigation"
   end

lib/lti/privacy_level_expander.rb

@@ -30,35 +30,23 @@ module Lti
       anonymous: ANONYMOUS
     }.freeze
 
-    def initialize(tool:, placement:, context:, collaboration: nil, opts: {})
-      @tool = tool
+    def initialize(placement, variable_expander)
       @placement = placement
-      @context = context
-      @collaboration = collaboration
-      @opts = opts.merge({tool: tool, collaboration: collaboration})
+      @variable_expander = variable_expander
     end
 
-    def expanded_variables
-      variable_expander.expand_variables!(@tool.set_custom_fields(@placement)).merge(parameter_hash)
+    def expanded_variables!(var_hash)
+      @variable_expander.expand_variables!(var_hash).merge(parameter_hash)
     end
 
     def supported_parameters
-      SUPPORTED_PARAMETERS_HASH[:anonymous] | SUPPORTED_PARAMETERS_HASH[@tool.workflow_state.to_sym]
+      SUPPORTED_PARAMETERS_HASH[:anonymous] | SUPPORTED_PARAMETERS_HASH[@variable_expander.tool.workflow_state.to_sym]
     end
 
     private
 
     def parameter_hash
-      variable_expander.enabled_capability_params(supported_parameters)
-    end
-
-    def variable_expander
-      @_varaible_expander ||= begin
-        Lti::VariableExpander.new(@opts[:domain_root_account],
-                                  @context,
-                                  @opts[:controller],
-                                  @opts)
-      end
+      @variable_expander.enabled_capability_params(supported_parameters)
     end
   end
 end

spec/lib/lti/privacy_level_expander_spec.rb

@@ -25,14 +25,17 @@ describe Lti::PrivacyLevelExpander do
   let(:placement) {'resource_selection'}
   let(:tool) { new_valid_tool(course) }
   let(:launch_url) { 'http://www.test.com/launch' }
-
-  let(:opts) do
-    {
-      current_user: user,
-      current_pseudonym: user.pseudonyms.first,
-      domain_root_account: course.root_account,
-      controller: double(request: {body: 'body content'})
-    }
+  let(:variable_expander) do
+    Lti::VariableExpander.new(
+      course.root_account,
+      course,
+      double(request: {body: 'body content'}),
+      {
+        current_user: user,
+        current_pseudonym: user.pseudonyms.first,
+        tool: tool
+      }
+    )
   end
 
   before do
@@ -40,15 +43,7 @@ describe Lti::PrivacyLevelExpander do
     tool.save!
   end
 
-  let(:helper) do
-    Lti::PrivacyLevelExpander.new(
-      tool: tool,
-      placement: placement,
-      context: course,
-      collaboration: nil,
-      opts: opts
-    )
-  end
+  let(:helper) { Lti::PrivacyLevelExpander.new(placement, variable_expander) }
 
   describe 'expanded_variables' do
     it 'expands custom fields' do
@@ -56,7 +51,7 @@ describe Lti::PrivacyLevelExpander do
         'custom_context_id' => Lti::Asset.opaque_identifier_for(course)
       }
 
-      expect(helper.expanded_variables).to include expected_params
+      expect(helper.expanded_variables!(tool.set_custom_fields(placement))).to include expected_params
     end
 
     it 'includes supported parameters' do
@@ -64,7 +59,7 @@ describe Lti::PrivacyLevelExpander do
         'context_label' => course.course_code
       }
 
-      expect(helper.expanded_variables).to include expected_params
+      expect(helper.expanded_variables!(Hash.new)).to include expected_params
     end
   end
 
@@ -77,15 +72,7 @@ describe Lti::PrivacyLevelExpander do
         tool
       end
 
-      let(:helper) do
-        Lti::PrivacyLevelExpander.new(
-          tool: tool,
-          placement: placement,
-          context: course,
-          collaboration: nil,
-          opts: opts
-        )
-      end
+      let(:helper) { Lti::PrivacyLevelExpander.new(placement, variable_expander) }
 
       it 'includes all supported parameters if privacy level is public' do
         expected_params = %w(com.instructure.contextLabel
@@ -107,15 +94,7 @@ describe Lti::PrivacyLevelExpander do
         tool
       end
 
-      let(:helper) do
-        Lti::PrivacyLevelExpander.new(
-          tool: tool,
-          placement: placement,
-          context: course,
-          collaboration: nil,
-          opts: opts
-        )
-      end
+      let(:helper) { Lti::PrivacyLevelExpander.new(placement, variable_expander) }
 
       it 'inlcudes anonymous and name only params if privacy level is name only' do
         expected_params = %w(com.instructure.contextLabel
@@ -134,15 +113,7 @@ describe Lti::PrivacyLevelExpander do
         tool
       end
 
-      let(:helper) do
-        Lti::PrivacyLevelExpander.new(
-          tool: tool,
-          placement: placement,
-          context: course,
-          collaboration: nil,
-          opts: opts
-        )
-      end
+      let(:helper) { Lti::PrivacyLevelExpander.new(placement, variable_expander) }
 
       it 'includes anonymous and email only params if privacy level is email only' do
         expected_params = %w(com.instructure.contextLabel
@@ -159,15 +130,7 @@ describe Lti::PrivacyLevelExpander do
         tool
       end
 
-      let(:helper) do
-        Lti::PrivacyLevelExpander.new(
-          tool: tool,
-          placement: placement,
-          context: course,
-          collaboration: nil,
-          opts: opts
-        )
-      end
+      let(:helper) { Lti::PrivacyLevelExpander.new(placement, variable_expander) }
 
       it 'includes anonymouse parameters only if privacy level is anonymous' do
         expected_params = %w(com.instructure.contextLabel)