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I'm new to Ruby. I'm trying to figure out how to write a nested case statement. Here is an example of what I am trying to do:

# cucumber, webrat paths.rb

  def path_to(page_name)

    case page_name

    when /the "?(.*)"? event registration homepage/ then
      case $1
      when '2011 CIO GL Global'  then '/event/index/id/236'
      when '2011 CIO IS Chicago' then '/event/index/id/275'
      when '2011 CIO ES Denver'  then '/event/index/id/217'
      when '2011 CIO ES Vancouver, BC' then '/event/index/id/234'
      else
        raise "Can't find mapping for \"#{$1}\" to a path.\n" +
          "Now, go and add a mapping in #{__FILE__}"
      end

    when /the contact match verification page/
      '/attendee/user-verification'
    end
  end

In my feature file it says:

When I go to the "2011 CIO IS Chicago" event registration homepage

It's failing on this step because its raising the exception mentioned above, even though I have it defined in my case statement above. What am I doing wrong?

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4
  • What is it returning instead? Your code looks like it should work. Commented Mar 28, 2011 at 20:30
  • Works for me. What version of Ruby are you using? Commented Mar 28, 2011 at 20:31
  • Works for me, using Ruby 1.9.2 Commented Mar 28, 2011 at 20:32
  • Are you having URLs with spaces in them? Sounds unusual. Commented Mar 28, 2011 at 20:58

5 Answers 5

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4

Yeah, the second question mark is confusing the regular expression.

The expression:

.*b?

can match the string "axb" in two ways, either with .* matching the entire thing, or with .* matching the 'ax' and 'b?' matching the 'b'. The regular expression algorithm is "greedy" - it prefers to match as much as it can as early as it can.

I'd rewrite the regular expression as:

    when /the "?([^"]*)"? event registration homepage/ then

to make sure that that $1 doesn't end up with any double quotes in it...

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2 Comments

do you mind giving a little explanation to how your regexp works? I'm having a hard time wrapping my brain around it.
The expression [^"] just matches any character which is not a double quote. So [^"]* matches any number of characters that are not double quotes.
1

Change 

 when /the "?(.*)"? event registration homepage/ then

to

 when /the "?(.*)" event registration homepage/ then
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3 Comments

alright, I've updated with the actual code that I am using.
will this still allow the double quotes to be optional?
Nope, this requires a double quote at the end.
1

It works for me. How are you testing it?

Update: Aha, it's because your regular expression is matching the trailing quote, so $1 ends in a quotation mark which is not present in your inner case.

There are a few ways to fix this.

  1. You could match "?[^"]*"?
  2. The selectors for the inner case could just end in ..."?'
  3. You could use a non-greedy match: "?(.*?)"?.
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0

The problem is in your regex. Try removing the last ? as it's causing the " to be optional and the greedy search up front (.*) is putting it in the match $1.

Observe:

> s = 'the "2011 CIO IS Chicago" event registration homepage'
> /the "?(.*)"? event registration homepage/.match s #=> <MatchData "the \"2011 CIO IS Chicago\" event registration homepage" 1:"2011 CIO IS Chicago\"">
> $1 #=> "2011 CIO IS Chicago\""
> /the "?(.*)" event registration homepage/.match s #=> #<MatchData "the \"2011 CIO IS Chicago\" event registration homepage" 1:"2011 CIO IS Chicago">
> $1 #=> "2011 CIO IS Chicago"

Edit: if you want the " to be optional you'll probably need to do something like: (?:"(.*)"|(.*)). And then you'll need to use a nil guard to find out which reference is returned. $1 || $2.

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I would approach this a little differently. In your cucumber feature, I suggest changing the wording like so:

When I go to the registration homepage for the event named "2011 CIO IS Chicago"

And in your paths.rb file I would handle all events with a single regexp, like so:

when /the registration homepage for the event named "?(.*)"?/ then
  event = Event.find_by_name($1)
  raise "could not find an event with name: #{$1}" if event.blank?
  event_path(event) 
  # or create the route manually like so:  
  # "event/index/id/#{event.id}"

This relies on your Event model having a method that can find an event given its name (in this case I assumed find_by_name), and a resourceful route set up for :events.

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4 Comments

thanks, good suggestion. unfortunately I can't look up the event in the database which is why I have to have this mapping.
Oh, I see. In that case, I think it may still be a good idea to add some kind of a lookup method, either in the form of a Cucumber helper or within the Event model class, so that the association between event names and IDs is in one place. Most likely you will need to write more examples involving events, and this is one approach to keeping things DRY.
Maybe I should clarify... I'm using cucumber to test a PHP application. I'm using the wire protocol to interact with the PHP code and Ruby step definitions to interact with the browser. Since I'm not testing a Ruby application, I can't use Ruby to interact with my PHP models. This is why I've got this ugly case statement in my paths.rb file.
Ah, I see. That explains everything.

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