JSON Matching

gistfile1.rb

class MyTestCase < MiniTest::Unit::TestCase
  # ...

  WILDCARD_MATCHER = Object.new

  def WILDCARD_MATCHER.==(other)
    true
  end

  def WILDCARD_MATCHER.is_a?(klass)
    false
  end

  def WILDCARD_MATCHER.inspect
    'WILDCARD_MATCHER'
  end

  def assert_json_matches(matcher, json)
    assert match_json(matcher, json), "Expected\n#{matcher.pretty_inspect}\nto match\n#{json.pretty_inspect}"
  end

  def match_json(matcher, json)
    if matcher.is_a? Array
      return false unless json.is_a? Array
      return false unless match_array matcher, json
    elsif matcher.is_a? Hash
      return false unless  json.is_a? Hash
      return false unless match_hash matcher, json
    elsif matcher.is_a? Regexp
      return false unless matcher =~ json
    else
      return false unless matcher == json
    end

    true
  end

  def match_array(matcher, array)
    return false unless matcher.length == array.length

    matcher = matcher.clone
    array   = array.clone

    begin
      # This might fail
      matcher.sort!
      array.sort!

      matched = []

      matcher.zip(array).each_with_index do |(v1, v2), i|
        matched << i if match_json v1, v2
      end

      matcher.delete_if.with_index { |_, i| matched.include? i }
      array.delete_if.with_index { |_, i| matched.include? i }
    rescue Exception
    end

    # O(N^2) matching for remaining items
    matcher.each do |v1|
      matched = false

      array.each_with_index do |v2, i|
        if match_json v1, v2
          matched = true
          array.delete_at i
          break
        end
      end

      return false unless matched
    end

    true
  end

  def match_hash(matcher, hash)
    return false unless matcher.length == hash.length
    return false unless matcher.keys.sort == hash.keys.sort
    matcher.keys.each do |k|
      return false unless match_json(matcher[k], hash[k])
    end

    true
  end
end

t = MyTestCase.new(nil)

raw_json_str = '{ "a": 1, "b": true, "c": [1,2,3,4], "d": "abcdef", "e": "0123456789", "f": null, "g": {"aa": 1, "bb": {"aaa": 1} }, "h": "whatever" }'

t.assert_json_matches({
  'a' => 1,
  'b' => true,
  'c' => [4,1,3,2],
  'd' => 'abcdef',
  'e' => /[0-9]{10}/,
  'f' => nil,
  'g' => {
    'aa' => 1,
    'bb' => {
      'aaa' => 1
    }
  },
  'h' => MyTestCase::WILDCARD_MATCHER
}, JSON.parse(raw_json_str) )