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
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.
