Minitest rspec or spec matchers and shared behaviours

gistfile1.rb

# 100.should be_multiple_of(10)

#rspec
Rspec::Matchers.define :be_multiple_of do |multiple|
  match do |number|
    number % multiple == 0
  end

  failure_message_for_should do |number|
    "Expected #{number} to be multiple of #{multiple}"
  end
end

# minitest
# assert_multiple_of 10, 100

module MiniTest::Assertions
  def assert_multiple_of(multiple, number, msg = nil)
    message = msg || "Expected #{number} to be multiple of #{multiple}"
    assert_equal 0, number % multiple, message
  end
end

# minitest::spec 
# 100.must_be_multiple_of 10
class Object
  def must_be_multiple_of(expected)
    assert_multiple_of expected, self
  end
end

#or 

Object.infect_an_assertion :assert_multiple_of, :must_be_multiple_of

#or 

Numeric.infect_an_assertion :assert_multiple_of, :must_be_multiple_of

# minitest -> spec mapping

infect_an_assertion :assert_equal, :must_equal
infect_an_assertion :assert_match, :must_match
infect_an_assertion :assert_empty, :must_be_empty, :unary # tell not have actual<->expected swap only one argument like array.must_be_empty(no argument here )


# convention
# minitest
assert_equal expected, actual

# spec 
actual.must_equal expected

#so 

[].must_be_empty(no arg to flip)
assert_empty []

Object.infect_an_assertion :assert_empty, :must_be_empty

class Object
  def must_be_empty
    assert_empty , self # error
  end
end

# converts to 
Object.infect_an_assertion :assert_empty, :must_be_empty, :unary

class Object
  def must_be_empty
    assert_empty self # happy :)
  end
end

###
# shared behavior
###
module SharedBehavior
end
class MyTestClass1
  include SharedBehavior
end
class MyTestClass2
  include SharedBehavior
end

# rspec way
shared_examples 'as implemented in shared behavior module' do
  it 'is as implemented in shared behavior module' do
    do_somthing = somthing_to_do
    do_somthing.should include(SharedBehavior)
  end
end

describe 'First example' do
  include_examples 'as implemented in shared behavior module'
end
describe 'Next example' do
  include_examples 'as implemented in shared behavior module'
end

# minitest way
describe 'First example' do
  include AsImplementedInShared
end
describe 'Next example' do
  include AsImplementedInShared
end

module AsImplementedInShared
  def self.included(spec_class)
    spec_class.class_eval do
      it 'as implemented in shared behavior' do
        do_somthing = self.class.desc
        do_somthing.must_include(SharedBehavior)
      end
    end
  end
end