allow observers to view all module content

test plan:
* make a course with modules with completion
requirements and sequential progress
* log in as an observer in the course
* should not be required to complete content to view it

closes #CNVS-9216

Change-Id: Id2ac39e8d1199bed0e2b17c3d04a58d5c7f4304c
Reviewed-on: https://gerrit.instructure.com/39622
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Hilary Scharton <hilary@instructure.com>

app/controllers/context_modules_controller.rb

@@ -374,11 +374,12 @@ class ContextModulesController < ApplicationController
               @progressions = ContextModuleProgression.where(:context_module_id => context_module_ids).each{|p| p.evaluate }
             end
           end
-          render :json => @progressions
-        else
+        elsif @context.grants_right?(@current_user, session, :participate_as_student)
           @progressions = @context.context_modules.active.order(:id).map{|m| m.evaluate_for(@current_user) }
-          render :json => @progressions
+        else
+          @progressions = []
         end
+        render :json => @progressions
       elsif !@context.feature_enabled?(:draft_state)
         redirect_to named_context_url(@context, :context_context_modules_url, :anchor => "student_progressions")
       elsif !@context.grants_right?(@current_user, session, :view_all_grades)

app/models/context_module.rb

@@ -175,7 +175,10 @@ class ContextModule < ActiveRecord::Base
       return true
     elsif !self.active?
       return false
+    elsif self.context.user_has_been_observer?(user)
+      return true
     end
+
     progression = self.evaluate_for(user)
     # if the progression is locked, then position in the progression doesn't
     # matter. we're not available.

spec/models/context_module_spec.rb

@@ -442,6 +442,34 @@ describe ContextModule do
       @module2.available_for?(@user, :tag => @tag2, :deep_check_if_needed => true).should be_false
     end
 
+    it "should be available to observers" do
+      course_module
+      @assignment = @course.assignments.create!(:title => "some assignment")
+      @tag = @module.add_item({:id => @assignment.id, :type => 'assignment'})
+      @module.completion_requirements = {@tag.id => {:type => 'must_view'}}
+      @module.save!
+      @student = User.create!(:name => "some name")
+      @course.enroll_student(@student)
+
+      @module2 = @course.context_modules.create!(:name => "another module")
+      @module2.prerequisites = "module_#{@module.id}"
+      @assignment2 = @course.assignments.create!(:title => 'a2')
+      @tag2 = @module2.add_item({:id => @assignment2.id, :type => 'assignment'})
+      @module2.completion_requirements = {@tag2.id => {:type => 'must_view'}}
+      @module2.save!
+
+      @module2.prerequisites.should_not be_empty
+      @module2.available_for?(@student, :tag => @tag2, :deep_check_if_needed => true).should be_false
+
+      @course.enroll_user(user, 'ObserverEnrollment', :enrollment_state => 'active', :associated_user_id => @student.id)
+      user_session(@user)
+
+      @module2.available_for?(@user, :tag => @tag2, :deep_check_if_needed => true).should be_true
+
+      @module2.update_attribute(:require_sequential_progress, true)
+      @module2.available_for?(@user, :tag => @tag2).should be_true
+    end
+
     it "should create an unlocked progression if there are prerequisites that are met" do
       course_module
       @user = User.create!(:name => "some name")

spec/selenium/context_modules_student_spec.rb

@@ -71,6 +71,24 @@ describe "context_modules" do
       context_modules[2].find_element(:css, '.context_module_criterion').should include_text(@module_2.name)
     end
 
+    it "should not lock modules for observers" do
+      @course.enroll_user(user, 'ObserverEnrollment', :enrollment_state => 'active', :associated_user_id => @student.id)
+      user_session(@user)
+
+      go_to_modules
+
+      # shouldn't show the teacher's "show student progression" button
+      ff('.module_progressions_link').should_not be_present
+
+      context_modules = ff('.context_module')
+      #initial check to make sure everything was setup correctly
+      ff('.context_module .progression_container').each do |item|
+        item.text.strip.should be_blank
+      end
+      get "/courses/#{@course.id}/assignments/#{@assignment_2.id}"
+      f('#content').should_not include_text("hasn't been unlocked yet")
+    end
+
     it "should show overridden due dates for assignments" do
       override = assignment_override_model(:assignment => @assignment_2)
       override.override_due_at(4.days.from_now)