RSpec matcher to allow for possible, not required, conditions

maybe_match.rb

require 'rspec/expectations'

# It would be better if we could change this to pending on the fly, but that happens in a higher scope, 
# so there's nothing but "pass" or "fail"
RSpec::Matchers.define :maybe_match do |expected|
  match do |actual|
    true
  end

  description do |actual|
    if actual == expected
      "FUZZY PASS: #{actual} actually matches #{expected}"
    else
      "FUZZY FAIL: #{actual} does not match #{expected}, but probably should"
    end
  end
end

RSpec::Matchers.define :maybe_be_within do |delta|
  chain :of do |expected|
    @expected = expected
  end

  match do |actual|
    true
  end

  description do |actual|
    distance = (actual - @expected).abs
    if distance <= delta
      "FUZZY PASS: #{actual} is within #{delta} of #{expected}"
    else
      "FUZZY FAIL: #{actual} is #{distance} away from #{expected} but probably should be within #{delta}"
    end
  end
end

# specify { "this".should maybe_match "that"}
# --> this does not match that, but probably should