add courses and subaccounts to qraphql AccountType

closes PLAT-5253
flag = none

Test Plan:
- verify that you can see courses and sub-accounts
  under the main account type in /graphiql

Change-Id: I98db4a0e64c70c9886171fc3e27bd14cfdc16df7
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/221285
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Marc Phillips <mphillips@instructure.com>
QA-Review: Xander Moffatt <xmoffatt@instructure.com>
Product-Review: Clint Furse <cfurse@instructure.com>

app/graphql/types/account_type.rb

@@ -31,5 +31,16 @@ module Types
       # batch load it in a reasonable way.
       object.resolved_outcome_proficiency&.outcome_proficiency_ratings
     end
+
+    field :courses_connection, CourseType.connection_type, null: true
+    def courses_connection
+      return unless object.grants_right?(current_user, :read_course_list)
+      object.associated_courses
+    end
+
+    field :sub_accounts_connection, AccountType.connection_type, null: true
+    def sub_accounts_connection
+      object.sub_accounts.order(:id)
+    end
   end
 end

spec/graphql/types/account_type_spec.rb

@@ -23,6 +23,8 @@ describe Types::AccountType do
   before(:once) do
     teacher_in_course(active_all: true)
     student_in_course(active_all: false)
+    account_admin_user
+    @sub_account = account_model parent_account: @course.root_account
   end
 
   let(:account) { @course.root_account }
@@ -43,4 +45,16 @@ describe Types::AccountType do
       account_type.resolve('proficiencyRatingsConnection { nodes { _id } }').sort
     ).to eq OutcomeProficiencyRating.all.map { |r| r.id.to_s }.sort
   end
+
+  it 'works for courses' do
+    expect(account_type.resolve('coursesConnection { nodes { _id } }', current_user: @admin)).to eq [@course.id.to_s]
+  end
+
+  it 'requires read_course_list permission' do
+    expect(account_type.resolve('coursesConnection { nodes { _id } }', current_user: @teacher)).to be_nil
+  end
+
+  it 'works for subaccounts' do
+    expect(account_type.resolve('subAccountsConnection { nodes { _id } }')).to eq [@sub_account.id.to_s]
+  end
 end