Custom Matcher's

[fluxsaas]

Hey,

i was a bit confused on how to create custom matchers, so i wanted to share a solution. You can include the module in rspec/others and use it:

show action e.g.:

response.body.should match_json_expression(JSONPatterns.user)

index action e.g.:

response.body.should match_json_expression(JSONPatterns.users(User.count))

# spec/support/json_patterns.rb
module JSONPatterns

  class ValidDateMatcher
    def ==(other)
      return DateTime.parse other rescue nil
    end
  end

  class NilOrIntegerMatcher
    def ==(other)
      other.nil? || other.is_a?(Integer)
    end
  end

  class NilOrStringMatcher
    def ==(other)
      other.nil? || other.is_a?(String)
    end
  end

  class << self

    def valid_date
      @DATE_MATCHER ||= ValidDateMatcher.new
    end

    def nil_or_integer
      @NIL_OR_INTEGER_MATCHER ||= NilOrIntegerMatcher.new
    end

    def nil_or_string
      @NIL_OR_STRING_MATCHER ||= NilOrStringMatcher.new
    end

    def user
      {
        id: Integer,
        created_at: valid_date,
        updated_at: valid_date,
        name: String,
        avatar: nil_or_string
      }
    end

    def users n
      [user] * n
    end

  end

end

[MiroslavCsonka]

Hi,

thanks very much for your example with NilOrStringMatcher I also got stuck with it. I played with little something and I would love to hear and opinion from someone else.

I liked your JSONPatterns but also sometimes I want to make sure, that some attributes (usually ids are correct) so I extended it a bit
https://gist.github.com/MiroslavCsonka/6919b62c222bf76ba13f

Let me please know what you think. If it makes sense I could udpate README with some examples