leave enrollments when a pseudonym is deleted

closes gh-1402

test plan
 - Create a user with two logins
 - have an enrollment tied to the sis id of one
 - delete that pseudonym
 - run a sis import enrollments referencing the
   deleted sis id
 - the enrollment should still be active

Change-Id: I350a998f53aae00662f2a133c17dd9596793ed6a
Reviewed-on: https://gerrit.instructure.com/178116
Tested-by: Jenkins
Reviewed-by: James Williams <jamesw@instructure.com>
Product-Review: Rob Orton <rob@instructure.com>
QA-Review: James Williams <jamesw@instructure.com>

lib/sis/enrollment_importer.rb

@@ -279,13 +279,8 @@ def process_batch
           end
 
           if enrollment_info.status =~ /\Aactive/i
-            if user.workflow_state != 'deleted' && pseudo.workflow_state != 'deleted'
-              enrollment.workflow_state = 'active'
-            else
-              enrollment.workflow_state = 'deleted'
-              message = "Attempted enrolling of deleted user #{enrollment_info.user_id} in course #{enrollment_info.course_id}"
-              @messages << SisBatch.build_error(enrollment_info.csv, message, sis_batch: @batch, row: enrollment_info.lineno, row_info: enrollment_info.row_info)
-            end
+            message = set_enrollment_workflow_state(enrollment, enrollment_info, pseudo, user)
+            @messages << SisBatch.build_error(enrollment_info.csv, message, sis_batch: @batch, row: enrollment_info.lineno, row_info: enrollment_info.row_info) if message
           elsif enrollment_info.status =~ /\Adeleted/i
             # we support creating deleted enrollments, but we want to preserve
             # the state for roll_back_data so only set workflow_state for new
@@ -389,6 +384,30 @@ def incrementally_update_account_associations
 
       private
 
+      def set_enrollment_workflow_state(enrollment, enrollment_info, pseudo, user)
+        message = nil
+        # the user is active, and the pseudonym is active
+        if user.workflow_state != 'deleted' && pseudo.workflow_state != 'deleted'
+          enrollment.workflow_state = 'active'
+          # the user is active, but the pseudonym is deleted, check for other active pseudonym
+        elsif user.workflow_state != 'deleted' && pseudo.workflow_state == 'deleted'
+          if @root_account.pseudonyms.active.where(user_id: user).where("sis_user_id != ? OR sis_user_id IS NULL", enrollment_info.user_id).exists?
+            enrollment.workflow_state = 'active'
+            message = "Enrolled a user #{enrollment_info.user_id} in course #{enrollment_info.course_id}, but referenced a deleted sis login"
+          else
+            message = invalid_active_enrollment(enrollment, enrollment_info)
+          end
+        else # the user is deleted
+          message = invalid_active_enrollment(enrollment, enrollment_info)
+        end
+        message
+      end
+
+      def invalid_active_enrollment(enrollment, enrollment_info)
+        enrollment.workflow_state = 'deleted'
+        "Attempted enrolling of deleted user #{enrollment_info.user_id} in course #{enrollment_info.course_id}"
+      end
+
       def enrollment_needs_due_date_recaching?(enrollment)
         unless %w(active inactive).include? enrollment.workflow_state_before_last_save
           return %w(active inactive).include? enrollment.workflow_state

spec/lib/sis/csv/enrollment_importer_spec.rb

@@ -930,6 +930,33 @@
     expect(student.enrollments.first).to be_deleted
   end
 
+  it "do not create enrollments for deleted pseudonyms except when they have an active pseudonym too" do
+    process_csv_data_cleanly(
+        "course_id,short_name,long_name,account_id,term_id,status",
+        "test_1,TC 101,Test Course 101,,,active"
+    )
+    process_csv_data_cleanly(
+        "user_id,login_id,first_name,last_name,email,status",
+        "student_user,user1,User,Uno,user@example.com,active"
+    )
+    p = Pseudonym.where(sis_user_id: "student_user").first
+    p.user.pseudonyms.create(account: p.account, sis_user_id: 'second_sis', unique_id: 'second_sis')
+    process_csv_data_cleanly(
+        "user_id,login_id,first_name,last_name,email,status",
+        "student_user,user1,User,Uno,user@example.com,deleted"
+    )
+    importer = process_csv_data(
+        "course_id,user_id,role,section_id,status,associated_user_id",
+        "test_1,student_user,student,,active,",
+    )
+    errors = importer.errors.map { |r| r.last }
+    expect(errors).to eq ["Enrolled a user student_user in course test_1, but referenced a deleted sis login"]
+
+    student = p.user
+    expect(student.enrollments.count).to eq 1
+    expect(student.enrollments.first).to be_active
+  end
+
   it "should not enroll users into deleted sections" do
     process_csv_data_cleanly(
       "course_id,short_name,long_name,account_id,term_id,status",