How to test for (ActiveRecord) object equality

Question

In Ruby 1.9.2 on Rails 3.0.3, I'm attempting to test for object equality between two Friend (class inherits from ActiveRecord::Base) objects.

The objects are equal, but the test fails:

Failure/Error: Friend.new(name: 'Bob').should eql(Friend.new(name: 'Bob'))

expected #<Friend id: nil, event_id: nil, name: 'Bob', created_at: nil, updated_at: nil>
     got #<Friend id: nil, event_id: nil, name: 'Bob', created_at: nil, updated_at: nil>

(compared using eql?)

Just for grins, I also test for object identity, which fails as I'd expect:

Failure/Error: Friend.new(name: 'Bob').should equal(Friend.new(name: 'Bob'))

expected #<Friend:2190028040> => #<Friend id: nil, event_id: nil, name: 'Bob', created_at: nil, updated_at: nil>
     got #<Friend:2190195380> => #<Friend id: nil, event_id: nil, name: 'Bob', created_at: nil, updated_at: nil>

Compared using equal?, which compares object identity,
but expected and actual are not the same object. Use
'actual.should == expected' if you don't care about
object identity in this example.

Can someone explain to me why the first test for object equality fails, and how I can successfully assert those two objects are equal?

Answer 1

Rails deliberately delegates equality checks to the identity column. If you want to know if two AR objects contain the same stuff, compare the result of calling #attributes on both.