Testing scopes with proxy_options in Rails 3

Greetings
I'm converting an rails 2 app to rails 3 and am having a time trying to
update tests on some named_scopes. I've search and searched and cannot
find anything that explains what I need to do. We are not using rspec
so I need to know if there is another way to convert these named scopes.

The problem seems to be with the proxy_options.

My Test:

class ClassInstructorTest < ActiveSupport::TestCase
  test "named_scope :find_instructor_for_a_course" do
    expected = { :select => "instr_id, netid",
              :conditions => ["crs_no = ? AND
                               term = ? AND
                               class_type = ? AND
                               class_no = ?", 'HA5503', 'F10', 'LEC', 1]
}
    assert_equal expected,
ClassInstructor.find_instructor_for_a_course('HA5503', 'F10', 'LEC',
1).proxy_options
   end
end

I get the following error when running my test:

1) Error:
test_named_scope_:find_instructor_for_a_course(ClassInstructorTest):
NoMethodError: undefined method `proxy_options' for [#<ClassInstructor
instr_id: "SMITH", netid: "hms25">]:ActiveRecord::Relation
    /test/unit/class_instructor_test.rb:10:in
`test_named_scope_:find_instructor_for_a_course'

Can anyone show me how to rewrite this test?
Thanks in advance.
--jc

I figured out that I needed to change how I was testing my scope.
Another forum site had this post by a guy named Ian (thanks Ian).

Ideally your unit tests should treat models (classes) and instances thereof as

black boxes. After all, it's not really the implementation you care about but the
behavior of the interface.

So instead of testing that the scope is implemented in a particular way (i.e.

with a particular set of conditions), try testing that it behaves correctly—that
it returns instances it should and doesn't return instances it shouldn't.