rspec users - Mar 2010 - Best way to match several attributes of an object?

When you need to check several properties of an object, what is the
best way to match them all?

I''m using the ''satisfy'' matcher at the moment but
perhaps there''s a
better way than this:
      flight.should satisfy { |f|
        f.booking_code            == @parsed_pnr_data[:pnr_number] &&
        f.depart_airport.code     == @parsed_pnr_data[:flights][0]
[:depart_airport_code] &&
        f.arrive_airport.code     == @parsed_pnr_data[:flights][0]
[:arrive_airport_code] &&
        f.depart_terminal         == @parsed_pnr_data[:flights][0]
[:depart_terminal] &&
        f.arrive_terminal         == @parsed_pnr_data[:flights][0]
[:arrive_terminal] &&
        f.start_date              == @parsed_pnr_data[:flights][0]
[:depart_date] &&
        f.end_date                == @parsed_pnr_data[:flights][0]
[:arrive_date]
      }

Many thanks

On Mar 30, 2010, at 9:23 AM, George wrote:
> When you need to check several properties of an object, what is the
> best way to match them all?
> 
> I''m using the ''satisfy'' matcher at the moment
but perhaps there''s a
> better way than this:
>      flight.should satisfy { |f|
>        f.booking_code            == @parsed_pnr_data[:pnr_number]
&&
>        f.depart_airport.code     == @parsed_pnr_data[:flights][0]
> [:depart_airport_code] &&
>        f.arrive_airport.code     == @parsed_pnr_data[:flights][0]
> [:arrive_airport_code] &&
>        f.depart_terminal         == @parsed_pnr_data[:flights][0]
> [:depart_terminal] &&
>        f.arrive_terminal         == @parsed_pnr_data[:flights][0]
> [:arrive_terminal] &&
>        f.start_date              == @parsed_pnr_data[:flights][0]
> [:depart_date] &&
>        f.end_date                == @parsed_pnr_data[:flights][0]
> [:arrive_date]
>      }
I don''t know if this is workable in your case or not, but I like to
design objects so you can compare them. Something like:

flight.should == Flight.new :booking_code => @parsed_pnr_data[:pnr_number],
.....

HTH,
David

Yep, that''s a fair point and may improve readability if I set up the
compare object in a before method.
Good idea, thanks David.
George

On Mar 30, 5:43?pm, David Chelimsky <dchelim... at gmail.com>
wrote:
> On Mar 30, 2010, at 9:23 AM, George wrote:
>
>
>
> > When you need to check several properties of an object, what is the
> > best way to match them all?
>
> > I''m using the ''satisfy'' matcher at the
moment but perhaps there''s a
> > better way than this:
> > ? ? ?flight.should satisfy { |f|
> > ? ? ? ?f.booking_code ? ? ? ? ? ?== @parsed_pnr_data[:pnr_number]
&&
> > ? ? ? ?f.depart_airport.code ? ? == @parsed_pnr_data[:flights][0]
> > [:depart_airport_code] &&
> > ? ? ? ?f.arrive_airport.code ? ? == @parsed_pnr_data[:flights][0]
> > [:arrive_airport_code] &&
> > ? ? ? ?f.depart_terminal ? ? ? ? == @parsed_pnr_data[:flights][0]
> > [:depart_terminal] &&
> > ? ? ? ?f.arrive_terminal ? ? ? ? == @parsed_pnr_data[:flights][0]
> > [:arrive_terminal] &&
> > ? ? ? ?f.start_date ? ? ? ? ? ? ?== @parsed_pnr_data[:flights][0]
> > [:depart_date] &&
> > ? ? ? ?f.end_date ? ? ? ? ? ? ? ?== @parsed_pnr_data[:flights][0]
> > [:arrive_date]
> > ? ? ?}
>
> I don''t know if this is workable in your case or not, but I like
to design objects so you can compare them. Something like:
>
> flight.should == Flight.new :booking_code =>
@parsed_pnr_data[:pnr_number], .....
>
> HTH,
> David
> _______________________________________________
> rspec-users mailing list
> rspec-us... at
rubyforge.orghttp://rubyforge.org/mailman/listinfo/rspec-users

On Mar 30, 2010, at 7:23 AM, George wrote:
> When you need to check several properties of an object, what is the
> best way to match them all?
> 
> I''m using the ''satisfy'' matcher at the moment
but perhaps there''s a
> better way than this:
>      flight.should satisfy { |f|
>        f.booking_code            == @parsed_pnr_data[:pnr_number]
&&
>        f.depart_airport.code     == @parsed_pnr_data[:flights][0]
> [:depart_airport_code] &&
>        f.arrive_airport.code     == @parsed_pnr_data[:flights][0]
> [:arrive_airport_code] &&
>        f.depart_terminal         == @parsed_pnr_data[:flights][0]
> [:depart_terminal] &&
>        f.arrive_terminal         == @parsed_pnr_data[:flights][0]
> [:arrive_terminal] &&
>        f.start_date              == @parsed_pnr_data[:flights][0]
> [:depart_date] &&
>        f.end_date                == @parsed_pnr_data[:flights][0]
> [:arrive_date]
>      }
> 
> Many thanks
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
I use a Comparable object whenever possible, as David said.  Other than that, I
just do one expectation per line.  That way when one fails, I know exactly where
the failure is.

Pat

>> When you need to check several properties of an object, what is the
>> best way to match them all?
In the mail library I use a custom matcher, which lets me do things like:

it "should handle |Minero Aoki <aamine at loveruby.net>|" do
  address = Mail::Address.new(''Minero Aoki <aamine at
loveruby.net>'')
  address.should break_down_to({
      :display_name => ''Minero Aoki'',
      :address      => ''aamine at loveruby.net'',
      :local        => ''aamine'',
      :domain       => ''loveruby.net'',
      :format       => ''Minero Aoki <aamine at
loveruby.net>'',
      :comments     => nil,
      :raw          => ''Minero Aoki <aamine at
loveruby.net>''})
end



The matcher in question is:



# encoding: utf-8
module CustomMatchers
  class BreakDownTo
    def initialize(expected)
      @expected = expected
    end

    def matches?(target)
      @target   = target
      @failed = false
      @expected.each_pair do |k,v|
        unless @target.send(k) == @expected[k]
          @failed = k
        end
      end
      !@failed
    end

    def failure_message
      "expected #{@failed} to be |#{@expected[@failed]}| " +
      "but was |#{@target.send(@failed)}|"
    end

    def megative_failure_message
      "expected #{@failed} not to be |#{@expected[@failed]}| " +
      "and was |#{@target.send(@failed)}|"
    end

  end

  # Actual matcher that is exposed.
  def break_down_to(expected)
    BreakDownTo.new(expected)
  end
end



-- 
http://rubyx.com/
http://lindsaar.net/
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