ensure login label is used on self enrollment

fixes CNVS-17962

If you have self enrollments enabled and set a custom label, that
custom label should be used when doing a self enrollment

Test

Given you have self enrollments enabled for a course
And you've set up a custom label for that course (by going to
accounts/self/settings)
When you go to a self enrollment link
The login label should be set to that text

Change-Id: I0c2fc08bbb69bfd72f87674e124d0e8ca7d73fb8
Reviewed-on: https://gerrit.instructure.com/48659
Tested-by: Jenkins
Reviewed-by: Clay Diffrient <cdiffrient@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Sterling Cobb <sterling@instructure.com>

app/controllers/self_enrollments_controller.rb

@@ -22,7 +22,13 @@ class SelfEnrollmentsController < ApplicationController
   include Api::V1::Course
 
   def new
+    @domain_root_account.reload
     js_env :PASSWORD_POLICY => @domain_root_account.password_policy
+    @login_label_name = t("email")
+
+    login_handle_name = @domain_root_account.login_handle_name
+    @login_label_name = login_handle_name if login_handle_name
+
     if !@current_user && delegated_authentication_url?
       store_location
       flash[:notice] = t('notices.login_required', "Please log in to join this course.")

app/views/self_enrollments/_authenticate_or_register.html.erb

@@ -1,11 +1,11 @@
 <form action="<%= self_enrollment_url %>" method="post" id="enroll_form" class="form-horizontal bootstrap-form">
   <%= registration_summary || content_tag(:p, mt(:getting_started, "You are enrolling in **%{course}**.", :course => @course.name)) %>
-  <p><%= t(:enter_email, "Please enter your email address:") %></p>
+  <p><%= t("Please enter your %{label_name}:", :label_name => @login_label_name) %></p>
   <input type="hidden" name="user[initial_enrollment_type]" value="student">
   <div class="control-group" id="email_info">
-    <label class="control-label" for="student_email"><%= t "labels.email", "Email" %></label>
+      <label class="control-label" for="student_email"><%= @login_label_name %></label>
     <div class="controls">
-      <input type="text" id="student_email" name="pseudonym[unique_id]">
+      <input type="text" id="student_email" name="pseudonym[unique_id]" placeholder="<%= @login_label_name %>">
     </div>
   </div>
   <div class="control-group" id="initial_action">

spec/controllers/self_enrollments_controller_spec.rb

@@ -51,5 +51,18 @@ describe SelfEnrollmentsController do
       get 'new', :self_enrollment_code => code
       expect(response).to be_success
     end
+
+    it "should default assign login_label_name to 'email'" do
+      get 'new', :self_enrollment_code => @course.self_enrollment_code
+      expect(assigns(:login_label_name)).to eq("Email")
+    end
+
+    it "should change login_label_name when set on domain_root_account" do
+      custom_label = "batman is the best"
+      Account.any_instance.stubs(:login_handle_name).returns(custom_label)
+
+      get 'new', :self_enrollment_code => @course.self_enrollment_code
+      expect(assigns(:login_label_name)).to eq(custom_label)
+    end
   end
 end