Fix user XXX didn’t exist for user enrollment

In order to facilitate better and more efficient debugging, this commit
improves the quality of the error messages reported by SIS imports. When
a user does not exist in users.csv, and enrollments in enrollments.csv
reference that user, the message "User XXX didn't exist for enrollment"
is not particularly useful. This commit adds course and section IDs to
the message to make it easier to search for broken rows.

Test plan:
  * Create or change an existing enrollments.csv file so that it
    references a user that doesn't exist.
  * Run the CSV through the SIS importer.
  * Check the error messages for the last import; the new error message
    should show up instead of the old one.

Change-Id: Ie3ea4d95c6877ef8c5b27cee9d530a6fdf0e6e6e
Fixes: SIS-1733
Reviewed-on: https://gerrit.instructure.com/71116
Tested-by: Jenkins
Reviewed-by: Ken Romney <kromney@instructure.com>
Reviewed-by: Tyler Pickett <tpickett@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Ken Romney <kromney@instructure.com>

lib/sis/enrollment_importer.rb

@@ -161,7 +161,9 @@ module SIS
             end
 
             unless pseudo
-              @messages << "User #{user_id} didn't exist for user enrollment"
+              err = "User not found for enrollment "
+              err << "(User ID: #{user_id}, Course ID: #{course_id}, Section ID: #{section_id})"
+              @messages << err
               next
             end
 

spec/lib/sis/enrollment_importer_spec.rb

@@ -2,21 +2,35 @@ require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper.rb')
 
 module SIS
   describe EnrollmentImporter do
+    let(:user_id) { "5235536377654" }
+    let(:course_id) { "82433211" }
+    let(:section_id) { "299981672" }
 
-    it 'does not break postgres if I give it integers' do
-      messages = []
-      EnrollmentImporter.new(Account.default, {}).process(messages, 2) do |importer|
-        enrollment = SIS::Models::Enrollment.new()
-        enrollment.course_id = 1
-        enrollment.section_id = 2
-        enrollment.user_id = 3
-        enrollment.role = 'student'
-        enrollment.status = 'active'
-        enrollment.start_date = Time.zone.today
-        enrollment.end_date = Time.zone.today
-        importer.add_enrollment(enrollment)
+    let(:enrollment) do
+      SIS::Models::Enrollment.new(
+        course_id: course_id,
+        section_id: section_id,
+        user_id: user_id,
+        role: 'student',
+        status: 'active',
+        start_date: Time.zone.today,
+        end_date: Time.zone.today
+      )
+    end
+
+    context 'gives a meaningful error message when a user does not exist for an enrollment' do
+      let(:messages) { [] }
+
+      before do
+        EnrollmentImporter.new(Account.default, {}).process(messages, 2) do |importer|
+          importer.add_enrollment(enrollment)
+        end
       end
-      expect(messages).not_to be_empty
+
+      it { expect(messages.first).to include("User not found for enrollment") }
+      it { expect(messages.first).to include("User ID: #{user_id}") }
+      it { expect(messages.first).to include("Course ID: #{course_id}") }
+      it { expect(messages.first).to include("Section ID: #{section_id}") }
     end
 
     context 'with a valid user ID but invalid course and section IDs' do