testing create action with nested resources - ruby-on-rails-3

Question

I have a bit of a confusing rSpec issue - depending how I write my code, either the tests that describe the 'failing' specs fail or the tests that describe the 'successful' specs fail.
Here are the tests for the create action:
describe "POST 'create'" do
describe "failure" do
before(:each) do
#attr = {name: "", type_of_group: ""}
#student_attr = [{name: "Joe", gender: "Male"}, {name: "sally twotrees", gender: "Female"}]
#create = post :create, student_group: #attr, student: #student_attr
end
it "should have the right title" do
#create
response.should have_selector('title', :content => "Create a new group" )
end
it "should render the 'new' page" do
#create
response.should render_template('new')
end
it "should not create a user" do
lambda do
post :create, student_group: #attr
end.should_not change {#user.student_groups.count}
end
it "should flash an error message" do
#create
flash[:error].should =~ /please/i
end
end
describe "success" do
before(:each) do
#attr = FactoryGirl.attributes_for(:student_group)
# #student_attr = {name: "test", gender: "Male"}
end
it "should create a student_group" do
lambda do
post :create, student_group: #attr
end.should change {#user.student_groups.count}.by(1)
end
it "should create students" # do
# lambda do
# post :create, student_group: #attr, student: #student_attr
# end.should change {#student_groups.students.count}.by(1)
# end
it "should flash a success message" do
post :create, student_group: #attr
flash[:success].should =~ /has been added/i
end
it "should redirect" do
post :create, student_group_id: #group, student_group: #attr
response.should be_redirect
end
end
end
All of the 'failure' tests fail with this error:
Failure/Error: #create = post :create, student_group: #attr, student: #student_attr
ActionView::Template::Error:
`#student_group[students_attributes]' is not allowed as an instance variable name
if I write the code in my controller this way:
def create
#params = params[:student_group][:students_attributes]
#student_group = #user.student_groups.build(params[:student_group])
if #student_group.save
### RE: 'defensive coding' https://stackoverflow.com/questions/14502508/undefined-method-for-nilnilclass-when-pushing-values-to-an-array
if #params.present?
### https://stackoverflow.com/questions/11355820/rails-3-2-iterate-through-an-array
#params.each do |student|
#student_group.students.create(name:"#{student[:name]}", gender: "#{student[:gender]}")
end
end
# new subject path
redirect_to class_path(#student_group), flash: { success: "#{#student_group.name} has been added successfully" }
else
#title = "Create a new group"
flash.now[:error] = "Something's gone wrong. Please try again!"
render 'new'
end
end
and all of the 'success' tests fail if the controller code is written like this:
def create
#params = params[:student_group][:students_attributes]
#student_group = #user.student_groups.build(params[:student_group])
### http://railsforum.com/viewtopic.php?pid=40056#p40056
if #params.present?
#student = Student.new
else
#student = #student_group.students.build(#params)
end
if #student_group.save
### RE: 'defensive coding' https://stackoverflow.com/questions/14502508/undefined-method-for-nilnilclass-when-pushing-values-to-an-array
if #params.present?
### https://stackoverflow.com/questions/11355820/rails-3-2-iterate-through-an-array
#params.each do |student|
#student_group.students.create(name:"#{student[:name]}", gender: "#{student[:gender]}")
end
end
# new subject path
redirect_to class_path(#student_group), flash: { success: "#{#student_group.name} has been added successfully" }
else
#title = "Create a new group"
flash.now[:error] = "Something's gone wrong. Please try again!"
render 'new'
end
end
the form code is here: https://stackoverflow.com/a/17591802/2128691

Answer 1

from the above code it seems that your controller code is really messed up. In case of nested attributes, u just have to save the parent object. the child objects get saved automatically if they are valid. Also u dont need to assign the params the some instance object. they should be used directly. a simple example of nested attributes can be
User
has_many :comments
accepts_nested_attributes_for :comments
Comment
belongs_to :user
ur controller code should be as
def create
#user = User.new(params[:user])
if #user.save
flash[:notice] = 'success'
redirect_to some_path and return
end
render 'new'
end
the rspec controller test case can be as
it "should create a user with comments if valid data is provided" do
post :create, "user"=>{"name"=>"Prasad", "comments_attributes"=>{"0"=>{"comment"=>"first comment"}, "1"=>{"comment"=>"second comment"}}, "commit"=>"Save"
user = assigns[:user] #assigns lets u access the instance variable from the controller in the spec
user.should be_valid
user.comments.count.should == 2 #check that all the child models are saved
user.name.should == "Prasad"
user.comments.first.comment.should == 'first comment'
user.comments.last.comment.should == 'second comment'
response.should be_redirect(some_path) #since u redirected in the code
end
seriously, u need to go through rails guides.

Answer 2

I ended up using this code:
def create
#student_group = #user.student_groups.new(params[:student_group])
#params = params[:student_group][:students_attributes]
#student_group = #user.student_groups.build(params[:student_group])
if #student_group.save
### RE: 'defensive coding' http://stackoverflow.com/questions/14502508/undefined-method-for-nilnilclass-when-pushing-values-to-an-array
if #params.present?
### http://stackoverflow.com/questions/11355820/rails-3-2-iterate-through-an-array
#params.each do |student|
#student_group.students.create(name:"#{student[:name]}", gender: "#{student[:gender]}")
end
end
redirect_to new_student_group_subject_path(#student_group), flash: { success: "#{#student_group.name} has been added successfully. Next, add the subjects for this group" }
else
### http://railsforum.com/viewtopic.php?pid=40056#p40056
#student = #student_group.students.build
#title = "Create a new group"
flash.now[:error] = "Something's gone wrong. Please try again!"
render 'new'
end
end