ryanb/expectations.md

## expectations.md

      
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              expectations.md
            
          
    Expectations

I took the ideas presented here and built a gem called Mustard. Check it out!
There are several expectation/assertion interfaces available for writing tests/specs. Here are some issues I have with them.
Test::Unit/MiniTest


The order of assert_equals feels backwards
Oh wait, that should be assert_equal (that too)
I like to write the subject first

MiniTest::Spec


Adds 30+ methods to Object
Any matchers you want to add are another method on Object
Still too few matchers, so it's ugly: foo.must_be :<, 10

Bacon


too.many.method.calls.to.simulate.english

RSpec Should


The space makes for some awkward syntaxes that cause warnings (when used with ==, >, etc.)
eq() and such aren't bad, but may need parenthesis
Pollutes the spec context with methods for each matcher

I haven't used the RSpec expect() interface enough to know cons.
Proposed Solution

# should returns an object which can have matchers called on it
5.should.eq 5
5.should.equal 5

# should_not can be used to do a reverse match
5.should_not.equal 7

# some comparison matchers
5.should.be_less_than 8
5.should.be_greater_than 3
5.should.be_lt 8
5.should.be_gt 3
5.should.be_gte 5
true.should.be_true
false.should.be_false

# call the method and see if it is true
[].should.be :empty?
5.should.be :between?, 3, 7

# add matchers
Should.matcher :be_empty do # any args will be passed into block
  empty? # runs in the context of the object and returns true/false
end
[].should.be_empty
[].should_not.be_empty # message: Expected [] to not be empty

# add matcher through class
Should.matcher :be_empty, BeEmptyMatcher
class BeEmptyMatcher
  # methods in here for defining behavior and messages.
end
I like this because it does not pollute the Object space much (just shouldand should_not). Also every method called after it is simply a matcher. No crazy method chains.
What do you think? If there's enough interest I'll write this up as a plugin for both RSpec-Core and MiniTest.