RSpec: difference between "should == ..." and "should eql(...)"

In RSpe开发者_开发问答c, what's the difference between using should == ... and should eql(...)? I noticed that the RSpec documentation always uses eql, but == is less typing and easier to read. What am I missing?

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It's rather simple, really: should == sends the == message to the test subject, should eql sends the eql? message to the test subject. In other words: the two different tests send two completely different messages which invoke two completely different methods and thus do two completely different things. In particular, eql? is stricter than == but less strict than equals?.

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They are usually equivalent, but not always:

1 ==   1.0 # => true
1.eql? 1.0 # => false