Using Pact data-diffs for fun and profit

example_pact_matcher_spec.rb

require "spec_helper"

require "pact/matchers"
require "pact/matchers/unix_diff_formatter"
require "term/ansicolor"

RSpec::Matchers.define :match_data do |expected|

  match do |actual|
    difference(actual).empty?
  end

  failure_message_for_should do |actual|
    diff = difference(actual)
    formatted_diff = Pact::Matchers::UnixDiffFormatter.call(diff, colour: true)
    colorize(formatted_diff)
  end

  def difference(actual)
    diff(expected, actual)
  end

  def colorize(s)
    s.split("\n").collect { |line|
      ::Term::ANSIColor.reset + line
    }.join("\n")
  end

  include Pact::Matchers

end

describe "stuff" do

  let(:data) do
    {
      "x" => 1,
      "y" => 2,
      "z" => {
        "foo" => 6
      }
    }
  end

  it "matches" do
    expect(data).to match_data({
      "x" => 2,
      "z" => {
        "foo" => 3
      }
    })
  end

end