v3.2.8 missing require for arel relation in predicate builder?

When I run tests against ActiveRecord with our driver I get this issue
with the AR code WRT Arel. On master this code no longer exists.

Is there a known defect in this file?

Bob

7 tests, 7 assertions, 0 failures, 0 errors, 0 skips
Roberts-MacBook-Pro-3:activerecord rbuck$ rake nuodb:rebuild_databases
Roberts-MacBook-Pro-3:activerecord rbuck$ ARCONN=nuodb ruby -Itest
test/cases/base_test.rb
Using nuodb with Identity Map off
/Users/rbuck/dev/sandboxes/github.com/drivers/drivers/rails/
activerecord/lib/active_record/relation/predicate_builder.rb:42:in
`block in build_from_hash': uninitialized constant Arel::Relation
(NameError)

Forget it. I tried using the AREL environment variable pointing to a
locally installed adel 3.0.2 directory, which caused this. Pointing to
[default] Github resolved this for unknown reasons.