diff --git a/lib/cdc_migration_testing/fixtures/assignment_override.rb b/lib/cdc_migration_testing/fixtures/assignment_override.rb
index 0dad6767996..c6b3a84da44 100644
--- a/lib/cdc_migration_testing/fixtures/assignment_override.rb
+++ b/lib/cdc_migration_testing/fixtures/assignment_override.rb
@@ -17,12 +17,18 @@
 #
 
 module CdcFixtures
+  class ForeignKeyNotSatisfied < StandardError
+  end
+
   def self.create_assignment_override
+    assignment = Assignment.first
+    raise CdcFixtures::ForeignKeyNotSatisfied unless assignment
+
     AssignmentOverride.new({
       workflow_state: 'default',
       title: 'default',
       set_id: 1,
-      assignment_id: 1
+      assignment_id: assignment.id
     })
   end
 end