Rspec equal method

user_224922 0
Viewed 20377

From what I have understood, the equal method checks if the object is the same.

person = Person.create!(:name => "David")
Person.find_by_name("David").should equal(person)

This should be true.

But aren't there two different objects here?

How could two objects be the same? I don't understand that.

rspec ruby
2 Answers

Rails and RSpec equality tests have a variety of choices.

Rails 3.2 ActiveRecord::Base uses the == equality matcher.

It returns true two different ways:

  • If self is the same exact object as the comparison object
  • If self is the same type as the comparison object and has the same ID

Note that ActiveRecord::Base has the == method which is aliased as eql?. This is different than typical Ruby objects, which define == and eql? differently.

RSpec 2.0 has these equality matchers in rspec-expectations:

a.should equal(b) # passes if a.equal?(b)
a.should eql(b) # passes if a.eql?(b)
a.should == b # passes if a == b

RSpec also has two equality matchers intended to have more of a DSL feel to them:

a.should be(b) # passes if a.equal?(b)
a.should eq(b) # passes if a == b

In your example you're creating a record then finding it.

So you have two choices for testing #find_by_name:

  • To test if it retrieves the exact same object OR an equivalent Person record with the same ID, then use should == or its equivalent a.should eql or its DSL version should eq

  • To test if it uses the exact same object NOT an equivalent Person record with the same ID, then use should equal or its DSL version should be

user_5287260
Related