Ryan Bigg

How many times do you use Cucumber to seed data by using a step such as this:

And there is a list:
  | name          |
  | GetUp people! |

Probably a lot, right? Good. Then this post is probably for you.

How many times have you done it and needed to specify an association in there too? Like this:

And there is a list:
  | name          | parameters[email_contains] |
  | GetUp people! | getup                      |

Probably a couple of times.

So what can be done?

As you may know, by using this syntax in Cucumber you get a variable which I always call “table” in my steps. You may call it something else. What matters is that it’s a Cucumber::Ast::Table object that has a method called hashes on it. This will return a Hash object for every single row minus one in your table. The minus one is the first row – the header row – which provides the keys for the hash. The remaining rows are the values for each of the hashes. In the first example, our hash is:

{ :name => "GetUp people!" }

In our second example, our hash is:

{ "name" => "GetUp people!", "parameters[email_contains]" => "getup" }

Bah! This won’t do!

Enter to_query

There’s a lovely method on Hash that will allow you to convert any Hash object to query parameters. It’s called to_query. The second Hash to_query output is this:

"name=GetUp+people%21&parameters%5Bemail_contains%5D=getup"

Eeew!

Query strings are not pretty

So to deal with query strings, Rack parses them into a Hash object (and Rails, a HashWithIndifferentAccess object) using the lovely Rack::Utils.parse_nested_query method. This forms the query string into the params hash which we have come to know and love. The very same params hash you use to create objects with.

See where I’m going with this? Great!

So we define our step like this:

Given /^there (is|are)\s?a?\s?lists?:$/ do |is_or_are, table|
  table.hashes.each do |hash|
    List.create!(Rack::Utils.parse_nested_query(hash.to_query))
  end
end

The regular expression is to match “there is a list:” or “there are lists:”, in case we want to create more than one. By passing in the parsed hash (and because we’re using accepts_nested_attributes_for, the model is actually ListParameters), we’re able to create not only the new List record, but also assign the ListParameter record too.

Not only for belongs_to

You can also assign has_manys through this too, although the syntax is a little bit more uglier. Again, providing you’re using accepts_nested_attributes_for for the has_many association, this should work just as well as if you posted it from a real form.

  And there is a link:
    | url               | clicks_attributes[0][user_id] |
    | http://google.com | 1                             |

How about that?!