rspec users - Jun 2009 - Can I set params in before[:each] block?

In my controller''s create method, I have:

@sub_context = @context.create_sub_context(params[:context][:name])

If I do not specify params in the "post :create" call in my controller
spec then I get the following error for each example:

You have a nil object when you didn''t expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]

So I see that it is trying to access :name when :context is nil which
can be avoided if I ensure each post :create includes a params for
[:context][:name] e.g.

post :create, :context => {"name" => "Seniors"}

I am wondering if there is a way to avoid having to specify params in
each and every example by adding some code to a before[:each] block?
For example, the params are redundant in some examples e.g.

    it "should save the context" do
      @context.should_receive(:save)
      post :create, :context => {"name" => "Seniors"}
    end

Thanks.

On 12 Jun 2009, at 08:34, Lee wrote:
> In my controller''s create method, I have:
>
> @sub_context = @context.create_sub_context(params[:context][:name])
>
> If I do not specify params in the "post :create" call in my
controller
> spec then I get the following error for each example:
>
> You have a nil object when you didn''t expect it!
> You might have expected an instance of ActiveRecord::Base.
> The error occurred while evaluating nil.[]
>
> So I see that it is trying to access :name when :context is nil which
> can be avoided if I ensure each post :create includes a params for
> [:context][:name] e.g.
>
> post :create, :context => {"name" => "Seniors"}
>
> I am wondering if there is a way to avoid having to specify params in
> each and every example by adding some code to a before[:each] block?
> For example, the params are redundant in some examples e.g.
>
>    it "should save the context" do
>      @context.should_receive(:save)
>      post :create, :context => {"name" =>
"Seniors"}
>    end
>
> Thanks.
There are several ways of doing this. The pattern I tend to us is to  
create a method that does the post, and contains default parameters  
which you can override if you want to.

describe "when the context has a name"
   def do_post(params = {})
     post :create, (:context => {"name" =>
"Seniors"}).merge(params)
   end

   it "should save the context" do
     @context.should_receive(:save)
     do_post
   end
end

Make sense?


Matt Wynne
http://beta.songkick.com
http://blog.mattwynne.net

Makes perfect sense. Thanks for the tip Matt!

On 12 June, 09:43, Matt Wynne <m... at mattwynne.net>
wrote:
> On 12 Jun 2009, at 08:34, Lee wrote:
>
>
>
> > In my controller''s create method, I have:
>
> > @sub_context = @context.create_sub_context(params[:context][:name])
>
> > If I do not specify params in the "post :create" call in my
controller
> > spec then I get the following error for each example:
>
> > You have a nil object when you didn''t expect it!
> > You might have expected an instance of ActiveRecord::Base.
> > The error occurred while evaluating nil.[]
>
> > So I see that it is trying to access :name when :context is nil which
> > can be avoided if I ensure each post :create includes a params for
> > [:context][:name] e.g.
>
> > post :create, :context => {"name" =>
"Seniors"}
>
> > I am wondering if there is a way to avoid having to specify params in
> > each and every example by adding some code to a before[:each] block?
> > For example, the params are redundant in some examples e.g.
>
> > ? ?it "should save the context" do
> > ? ? ?@context.should_receive(:save)
> > ? ? ?post :create, :context => {"name" =>
"Seniors"}
> > ? ?end
>
> > Thanks.
>
> There are several ways of doing this. The pattern I tend to us is to ?
> create a method that does the post, and contains default parameters ?
> which you can override if you want to.
>
> describe "when the context has a name"
> ? ?def do_post(params = {})
> ? ? ?post :create, (:context => {"name" =>
"Seniors"}).merge(params)
> ? ?end
>
> ? ?it "should save the context" do
> ? ? ?@context.should_receive(:save)
> ? ? ?do_post
> ? ?end
> end
>
> Make sense?
>
> Matt Wynnehttp://beta.songkick.comhttp://blog.mattwynne.net
>
> _______________________________________________
> rspec-users mailing list
> rspec-us... at
rubyforge.orghttp://rubyforge.org/mailman/listinfo/rspec-users

On 6/12/09 1:43 AM, Matt Wynne wrote back to Lee who
said:
>> I am wondering if there is a way to avoid having to specify params in
>> each and every example by adding some code to a before[:each] block?
> There are several ways of doing this. The pattern I tend to us is to
> create a method that does the post, and contains default parameters
> which you can override if you want to.
For contrast, I''ll describe the method I prefer.  The purpose of this
approach is to simplify and homogenize the interface of the "do it"
routine. By localizing the params in @instance variables, the raw
do_action() is a) easily called by you or the shared example group, b)
consistently named - the shared example doesn''t have to care what
action
is being done, and c) overridden with parameters at any level of nested
describe()s as you need.

describe "something" do
  before :each do
     @params = { :default => ''values'' }
  end
  sub do_action
     post :create, @params
  end
  it_should_behave_like "some shared example group"
     # shared example calls back to our do_action, by convention
  describe "something else" do
     before do
       @params[:special_for_something_else] = ''setting''
       # other setup
     end

     it "whatever" do
       @params[:special_for_whatever] = ''value''
       do_action
     end
  end
end

Randy