update pace duration calculation to include day enrolled

fixes LS-3582
flag=none

test plan:
  - tests pass

qa risk: low

Change-Id: Ifdc4dd0ff12df1ca7b0b26a450de634e81ec5f34
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/305148
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Robin Kuss <rkuss@instructure.com>
QA-Review: Robin Kuss <rkuss@instructure.com>
Product-Review: Davis Hyer <dhyer@instructure.com>

app/models/course_pace.rb

@@ -94,8 +94,16 @@ class CoursePace < ActiveRecord::Base
     end
   end
 
+  # We need to add one day to the sum of durations here to
+  # account for the oddity of the first item's set due date.
+  # If a user is enrolled via a pace item with a duration of
+  # one day on Jan 1 at 11:58pm, their due date would be on
+  # Jan 2 at 11:59pm. If that same user were enrolled on Jan
+  # 2 at 12:00am, their due date would be Jan 3 at 11:59pm.
+  # While this oddity of finishing out the current day exists,
+  # we will always need to add one to the sum of durations.
   def duration
-    course_pace_module_items.sum(:duration)
+    course_pace_module_items.sum(:duration) + 1
   end
 
   def valid_secondary_context

spec/models/course_pace_spec.rb

@@ -160,8 +160,8 @@ describe CoursePace do
   end
 
   describe "#duration" do
-    it "returns 0 if there are no module items" do
-      expect(@course_pace.duration).to eq 0
+    it "returns 1 if there are no module items" do
+      expect(@course_pace.duration).to eq 1
     end
 
     context "multiple paced module items exist" do
@@ -171,8 +171,8 @@ describe CoursePace do
         end
       end
 
-      it "returns the sum of all item durations" do
-        expect(@course_pace.duration).to eq 2
+      it "returns the sum of all item durations, taking into account the day of enrollment" do
+        expect(@course_pace.duration).to eq 3
       end
     end
   end

spec/requests/pace_contexts_spec.rb

@@ -54,7 +54,7 @@ describe "Pace Contexts API" do
         applied_pace_json = course_json["applied_pace"]
         expect(applied_pace_json["name"]).to eq course.name
         expect(applied_pace_json["type"]).to eq "Course"
-        expect(applied_pace_json["duration"]).to eq 0
+        expect(applied_pace_json["duration"]).to eq 1
         expect(Time.parse(applied_pace_json["last_modified"])).to be_within(1.second).of(default_pace.published_at)
       end
 

spec/selenium/course_paces/coursepaces_landing_page_spec.rb

@@ -105,7 +105,7 @@ describe "course pace landing page" do
       expect(course_pace_context_table).to be_displayed
       expect(number_of_students.text).to include("1")
       expect(number_of_sections.text).to include("2")
-      expect(default_duration.text).to include("2 days")
+      expect(default_duration.text).to include("3 days")
     end
   end