Add context_name to calendar events api

flag=none
refs: MBL-14399

Test plan:
- Enroll a student in a course
- Create and publish an assignment in the course and set its due date to
some day this month
- Create a calendar event on the user's calendar
- As the student, query the calendar_events api for the assignment
  - Something like: /api/v1/calendar_events
    ?type=assignment
    &start_date=2020-05-01
    &end_date=2020-05-30
    &context_codes[]=course_1
- The context_name should be included
- As the student, give the course a nickname
- The context_name should be the nickname of the course
- As the student, query the calendar_events api for the calendar event
  - Something like: /api/v1/calendar_events
    ?start_date=2020-05-01
    &end_date=2020-05-30
- The context_name should be included

Change-Id: Ie5336637824d3241d39b7fbb6dcb083e3ec25cdc
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/237393
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Ben Nelson <bnelson@instructure.com>
Reviewed-by: Rob Orton <rob@instructure.com>
QA-Review: Ben Nelson <bnelson@instructure.com>
Product-Review: Ben Nelson <bnelson@instructure.com>

app/controllers/calendar_events_api_controller.rb

@@ -71,6 +71,11 @@ require 'atom'
 #           "description": "if specified, it indicates which calendar this event should be displayed on. for example, a section-level event would have the course's context code here, while the section's context code would be returned above)",
 #           "type": "string"
 #         },
+#         "context_name": {
+#           "description": "the context name of the calendar this event belongs to (course, user or group)",
+#           "example": "Chemistry 101",
+#           "type": "string"
+#         },
 #         "all_context_codes": {
 #           "description": "a comma-separated list of all calendar contexts this event is part of",
 #           "example": "course_123,course_456",

lib/api/v1/calendar_event.rb

@@ -97,6 +97,7 @@ module Api::V1::CalendarEvent
       hash['all_context_codes'] = Context.context_code_for(event)
     end
     hash['context_code'] ||= Context.context_code_for(event)
+    hash['context_name'] = context.try(:nickname_for, user)
 
     hash['parent_event_id'] = event.parent_calendar_event_id
     # events are hidden when section-specific events override them
@@ -193,6 +194,7 @@ module Api::V1::CalendarEvent
       hash['html_url'] = hash['assignment']['html_url'] if hash['assignment'].include?('html_url')
     end
     hash['context_code'] = Context.context_code_for(assignment)
+    hash['context_name'] = assignment.context.try(:nickname_for, user)
     hash['start_at'] = hash['end_at'] = assignment.due_at
     hash['url'] = api_v1_calendar_event_url("assignment_#{assignment.id}")
     if assignment.applied_overrides.present?

spec/apis/v1/calendar_events_api_spec.rb

@@ -30,7 +30,7 @@ describe CalendarEventsApiController, type: :request do
       'all_context_codes', 'all_day', 'all_day_date', 'child_events', 'child_events_count', 'comments',
       'context_code', 'created_at', 'description', 'duplicates', 'end_at', 'hidden', 'html_url',
       'id', 'location_address', 'location_name', 'parent_event_id', 'start_at',
-      'title', 'type', 'updated_at', 'url', 'workflow_state'
+      'title', 'type', 'updated_at', 'url', 'workflow_state', 'context_name'
     ]
     expected_slot_fields = (expected_fields + ['appointment_group_id', 'appointment_group_url', 'can_manage_appointment_group', 'available_slots', 'participants_per_appointment', 'reserve_url', 'participant_type', 'effective_context_code'])
     expected_reservation_event_fields = (expected_fields + ['appointment_group_id', 'appointment_group_url', 'can_manage_appointment_group', 'effective_context_code', 'participant_type'])
@@ -1458,7 +1458,7 @@ describe CalendarEventsApiController, type: :request do
     expected_fields = [
       'all_day', 'all_day_date', 'assignment', 'context_code', 'created_at',
       'description', 'end_at', 'html_url', 'id', 'start_at', 'title', 'type', 'updated_at',
-      'url', 'workflow_state'
+      'url', 'workflow_state', 'context_name'
     ]
 
     it 'should return assignments within the given date range' do