Best way to match several attributes of an object?

Testing RSpec
1

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

2

On Mar 30, 2010, at 9:23 AM, George wrote:

[: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

3

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

4

On Mar 30, 2010, at 7:23 AM, George wrote:

[:arrive_airport_code] &&
Many thanks

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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

5

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 A. [email protected]|” do
address = Mail::Address.new(‘Minero A. [email protected]’)
address.should break_down_to({
:display_name => ‘Minero A.’,
:address => ‘[email protected]’,
:local => ‘aamine’,
:domain => ‘loveruby.net’,
:format => ‘Minero A. [email protected]’,
:comments => nil,
:raw => ‘Minero A. [email protected]’})
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