Problem to mock association proxy

Testing RSpec
1

Hello, I’m trying learn Rspec but having problems to understand when and
how
user mocks and stubs.
I have a properties_controller with to before_filter actions
(check_administrator_role e load_user)… to access index action of
properties_controller I need have a params[:user] and this parameter
will be
used to load ther user in method load_user …

Like bellow:

before_filter :check_administrator_role
before_filter :load_user

GET /properties

def index
@properties = @user.properties
end

private
def load_user
@user = User.find(params[:user_id])
if @user.nil?
flash[:notice] = “Registro não encontrado”
redirect_to root_path
end
end

But I don’t know how test index and load_user without fixtures, take a
look
on my specs:

describe PropertiesController do

def mock_property(stubs={})
@mock_property ||= mock_model(Property, stubs)
end

before do
@current_user = mock_model(User, :id => 1)
controller.stub!(:check_administrator_role).and_return(true)
@user = mock_model(User, :id=>1)
controller.stub!(:load_user).and_return(@user)
end

describe “responding to GET index” do

it "should expose all properties of given user as @properties" do
  @user.should_receive(:properties).and_return([mock_property])
  get :index
  assigns[:properties].should == [mock_property]
end

end

But I having this error:

NoMethodError in ‘PropertiesController responding to GET index should
expose
all properties of given user as @properties’
You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.properties
/Users/daniellopes/Trabalhos/luvima/luvima/app/controllers/properties_controller.rb:8:in
`index’
./spec/controllers/properties_controller_spec.rb:21:

So, how is the right way to mock associated records?

Thanks.

Atenciosamente,

Daniel L.  Area Criações
Design, Websites e Sistemas Web

Visite: http://www.areacriacoes.com.br/projects
http://blog.areacriacoes.com.br/

55 (31) 3077-4560 / 55 (31) 8808-8748 / 55 (31) 8737-7501

2

On 5 Dec 2008, at 13:42, Daniel L. wrote:

NoMethodError in ‘PropertiesController responding to GET index
should expose all properties of given user as @properties’
You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.properties
/Users/daniellopes/Trabalhos/luvima/luvima/app/controllers/
properties_controller.rb:8:in `index’
./spec/controllers/properties_controller_spec.rb:21:

So, how is the right way to mock associated records?

Hi Daniel

The error you are seeing is because the assignment to @user happens
inside #load_user: the live code never call @user = load_user`. As
far as possible, you want to avoid modifying objects under test -
private methods are only the business of instances of that class.
It’s much safer in this case to do

User.should_receive(:find).and_return(@user)

That way, the filter will run as normal.

As for the association - it’s actually irrelevant what that returns.
All you care is that whatever comes out of @user.properties is
assingned to the view. I tend to use symbols to represent objects
(including arrays) that get passed around. For example:

describe PropertiesController do

Not needed

def mock_property(stubs={})

@mock_property ||= mock_model(Property, stubs)

end

before do
controller.stub!(:check_administrator_role).and_return(true)
@user = mock_model(User, :id=>1, :properties => :user_properties)
User.stub!(:find).and_return(@user)
end

describe “responding to GET index” do
it “should expose all properties of given user as @properties” do
get :index
assigns[:properties].should == :user_properties
end
end

end

HTH

Ashley

–
http://www.patchspace.co.uk/

3

Thanks Ashley, now the tests passed… but I want understand one thing:
This line is only saying that @properties (assigned[:properties]) have
some
value … is that?
assigns[:properties].should == :user_properties

I can change above to assigns[:properties].should_not be_nill and the
semantic value will be the same, right?

Thanks…

Atenciosamente,

Daniel L.  Area Criações
Design, Websites e Sistemas Web

Visite: http://www.areacriacoes.com.br/projects
http://blog.areacriacoes.com.br/

55 (31) 3077-4560 / 55 (31) 8808-8748 / 55 (31) 8737-7501

On Fri, Dec 5, 2008 at 6:16 PM, Ashley M.

4

Thanks Ashley, you right.
Atenciosamente,

Daniel L.  Area Criações
Design, Websites e Sistemas Web

Visite: http://www.areacriacoes.com.br/projects
http://blog.areacriacoes.com.br/

55 (31) 3077-4560 / 55 (31) 8808-8748 / 55 (31) 8737-7501

On Fri, Dec 5, 2008 at 6:41 PM, Ashley M.

5

On 5 Dec 2008, at 20:26, Daniel Area Criações wrote:

This line is only saying that @properties (assigned[:properties])
have some value … is that?
assigns[:properties].should == :user_properties

I can change above to assigns[:properties].should_not be_nill and
the semantic value will be the same, right?

Ah no, the semantic value is different because this would also pass:

def index
@properties = “vegetable soup”
end

Yet that does not implement the same behaviour.

When you write a behaviour example, always ask the question “What
could I realistically write that could pass this but not give the
desired behaviour?” That way you will avoid false confidence in specs
where the behaviour could be broken in the future (perhaps during
refactoring), but RSpec still reports success.

Ashley

–
http://www.patchspace.co.uk/