Custom RSPec matcher for detailed hash compasion and diff

detailed_hash_diff.rb

require 'facets/hash/recurse'

# Usage:
#   expect(actual).to match_hash(expected)
#
RSpec::Matchers.define :match_hash do |expected|
  match do |actual|
    # Sort hashes before comparing so that the diff only shows actual changes between keys and
    # values.
    actual   = actual.recurse   {|h| h.sort_by {|k,v| k.to_s }.to_h }
    expected = expected.recurse {|h| h.sort_by {|k,v| k.to_s }.to_h }

    is_match = actual == expected
    unless is_match
      system(
        # If [diff-so-fancy](https://github.com/so-fancy/diff-so-fancy) is available, use it
        if (system('which diff-so-fancy >/dev/null'); $?.success?)
          "git diff $(echo '#{JSON.pretty_generate(expected)}' | git hash-object -w --stdin) " +
                   "$(echo '#{JSON.pretty_generate(actual  )}' | git hash-object -w --stdin)  | diff-so-fancy cat -"
        else
          "git diff $(echo '#{JSON.pretty_generate(expected)}' | git hash-object -w --stdin) " +
                   "$(echo '#{JSON.pretty_generate(actual  )}' | git hash-object -w --stdin) --word-diff | cat -"
        end,
        out: $stdout,
        err: :out
      )
    end
    is_match
  end

  failure_message { 'Look at the Diff above! ^^^' }
end

thanks for explaining, very useful gist 👍