Add presenter to membership service controller index action

fixes PLAT-1343

Test plan:
* Using a course with sufficient users hit the following endpoint
  /api/lti/courses/:course_id/membership_service
  using a user's access token
* The endpoint supports three query params
  page
  per_page
  role
* At the moment the role parameter is preserved in the nextPage url
  but doesn't have any effect on what the endpoint returns
* Ensure that the nextPage url query params are preserved and that the
  page param increments properly
* Ensure that per_page defaults to Api.per_page and that it cannot
  exceed Api.max_per_page
* Ensure that the json objects that are returned conform to the format
  detailed here:

  http://www.imsglobal.org/lti/model/mediatype/application/vnd/ims/lis/v2/membershipcontainer%2Bjson/index.html#Introduction

* Ensure that the list of users returned by the membership service
  includes only those users that the requesting user has permission to
  view

Change-Id: I9d25dce6678e5bf04719469a3c38392f3f0d1d68
Reviewed-on: https://gerrit.instructure.com/75821
Reviewed-by: Nathan Mills <nathanm@instructure.com>
Tested-by: Jenkins
QA-Review: August Thornton <august@instructure.com>
Product-Review: Andrew Butterfield <abutterfield@instructure.com>

Author: Andrew Butterfield

app/controllers/lti/membership_service_controller.rb

@@ -20,7 +20,18 @@ class MembershipServiceController < ApplicationController
     before_filter :require_user
 
     def index
-      render json: { hello: :world }
+      @page = MembershipService::PagePresenter.new(@context,
+                                                   @current_user,
+                                                   request.base_url,
+                                                   membership_service_params)
+      render json: @page
+    end
+
+    private
+
+    def membership_service_params
+      keys = %w(role page per_page)
+      params.select { |k,_| keys.include?(k) }
     end
   end
 end

spec/controllers/lti/membership_service_controller_spec.rb

@@ -26,9 +26,137 @@ module Lti
       end
 
       describe "#index" do
-        it 'requires a user' do
+        context 'without access token' do
+          it 'requires a user' do
+            get 'index', course_id: @course.id
+            assert_unauthorized
+          end
+        end
+
+        context 'with access token' do
+          before(:each) do
+            pseudonym(@teacher)
+            @teacher.save!
+            token = @teacher.access_tokens.create!(purpose: 'test').full_token
+            @request.headers['Authorization'] = "Bearer #{token}"
+          end
+
+          it 'outputs the expected data in the expected format at the top level' do
+            get 'index', course_id: @course.id
+            hash = json_parse.with_indifferent_access
+            expect(hash.keys.size).to eq(6)
+
+            expect(hash.fetch(:@id)).to be_nil
+            expect(hash.fetch(:@type)).to eq 'Page'
+            expect(hash.fetch(:@context)).to eq 'http://purl.imsglobal.org/ctx/lis/v2/MembershipContainer'
+            expect(hash.fetch(:differences)).to be_nil
+            expect(hash.fetch(:nextPage)).to be_nil
+            expect(hash.fetch(:pageOf)).not_to be_nil
+          end
+
+          it 'outputs the expected data in the expected format at the container level' do
+            get 'index', course_id: @course.id
+            hash = json_parse.with_indifferent_access
+            container = hash[:pageOf]
+
+            expect(container.size).to eq 5
+            expect(container.fetch(:@id)).to be_nil
+            expect(container.fetch(:@type)).to eq 'LISMembershipContainer'
+            expect(container.fetch(:@context)).to eq 'http://purl.imsglobal.org/ctx/lis/v2/MembershipContainer'
+            expect(container.fetch(:membershipPredicate)).to eq 'http://www.w3.org/ns/org#membership'
+            expect(container.fetch(:membershipSubject)).not_to be_nil
+          end
+
+          it 'outputs the expected data in the expected format at the context level' do
+            get 'index', course_id: @course.id
+            hash = json_parse.with_indifferent_access
+            @course.reload
+            context = hash[:pageOf][:membershipSubject]
+
+            expect(context.size).to eq 5
+            expect(context.fetch(:@id)).to be_nil
+            expect(context.fetch(:@type)).to eq 'Context'
+            expect(context.fetch(:name)).to eq @course.name
+            expect(context.fetch(:contextId)).to eq @course.lti_context_id
+            expect(context.fetch(:membership)).not_to be_nil
+          end
+
+          it 'outputs the expected data in the expected format at the membership level' do
+            get 'index', course_id: @course.id
+            hash = json_parse.with_indifferent_access
+            @teacher.reload
+            memberships = hash[:pageOf][:membershipSubject][:membership]
+
+            expect(memberships.size).to eq 1
+
+            membership = memberships[0]
+
+            expect(membership.size).to eq 4
+            expect(membership.fetch(:@id)).to be_nil
+            expect(membership.fetch(:status)).to eq IMS::LIS::Statuses::SimpleNames::Active
+            expect(membership.fetch(:role)).to match_array([IMS::LIS::Roles::Context::URNs::Instructor])
+
+            member = membership.fetch(:member)
+            expect(member.fetch(:@id)).to be_nil
+            expect(member.fetch(:name)).to eq @teacher.name
+            expect(member.fetch(:img)).to eq @teacher.avatar_image_url
+            expect(member.fetch(:email)).to eq @teacher.email
+            expect(member.fetch(:familyName)).to eq @teacher.last_name
+            expect(member.fetch(:givenName)).to eq @teacher.first_name
+            expect(member.fetch(:resultSourcedId)).to be_nil
+            expect(member.fetch(:sourcedId)).to be_nil
+            expect(member.fetch(:userId)).to eq(@teacher.lti_context_id)
+          end
+        end
+      end
+    end
+
+    context 'course with multiple enrollments' do
+      before(:each) do
+        course_with_teacher
+        @course.enroll_user(@teacher, 'TeacherEnrollment', enrollment_state: 'active')
+        @ta = user_model
+        @course.enroll_user(@ta, 'TaEnrollment', enrollment_state: 'active')
+        @student = user_model
+        @course.enroll_user(@student, 'StudentEnrollment', enrollment_state: 'active')
+
+        pseudonym(@teacher)
+        @teacher.save!
+        token = @teacher.access_tokens.create!(purpose: 'test').full_token
+        @request.headers['Authorization'] = "Bearer #{token}"
+      end
+
+      describe '#as_json' do
+        it 'provides the right next_page url when no page/per_page/role params are given' do
+          Api.stubs(:per_page).returns(1)
           get 'index', course_id: @course.id
-          assert_unauthorized
+          hash = json_parse.with_indifferent_access
+
+          uri = URI(hash.fetch(:nextPage))
+          expect(uri.scheme).to eq 'http'
+          expect(uri.host).to eq 'test.host'
+          expect(uri.path).to eq "/api/lti/courses/#{@course.id}/membership_service"
+          expect(uri.query).to eq 'page=2&per_page=1'
+        end
+
+        it 'provides the right next_page url when page/per_page/role params are given' do
+          Api.stubs(:per_page).returns(1)
+          get 'index', course_id: @course.id, page: 2, per_page: 1, role: 'Instructor'
+          hash = json_parse.with_indifferent_access
+
+          uri = URI(hash.fetch(:nextPage))
+          expect(uri.scheme).to eq 'http'
+          expect(uri.host).to eq 'test.host'
+          expect(uri.path).to eq "/api/lti/courses/#{@course.id}/membership_service"
+          expect(uri.query).to eq 'page=3&per_page=1&role=Instructor'
+        end
+
+        it 'returns nil for the next page url when the last page in the collection was requested' do
+          Api.stubs(:per_page).returns(1)
+          get 'index', course_id: @course.id, page: 3, per_page: 1, role: 'Instructor'
+          hash = json_parse.with_indifferent_access
+
+          expect(hash.fetch(:nextPage)).to be_nil
         end
       end
     end