line_items_controller.rb

class LineItemsController < ApplicationController
  # GET /line_items
  # GET /line_items.xml
  def index
    @line_items = LineItem.all

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @line_items }
    end
  end

  # GET /line_items/1
  # GET /line_items/1.xml
  def show
    @line_item = LineItem.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @line_item }
    end
  end

  # GET /line_items/new
  # GET /line_items/new.xml
  def new
    @line_item = LineItem.new

    respond_to do |format|
      format.html # new.html.erb
      format.xml  { render :xml => @line_item }
    end
  end

  # GET /line_items/1/edit
  def edit
    @line_item = LineItem.find(params[:id])
  end

  # POST /line_items
  # POST /line_items.xml
  def create
    @cart = find_or_create_cart
    product = Product.find[params[:product_id]] #params is what was passed,
    #and we ask for product_id out of that param hash for the find method of the Product
    #array.
    @line_item = @cart.line_items.build(:product => product)
    
    respond_to do |format|
      if @line_item.save #redirect to sends you to cart page, not line_item again!
        format.html { redirect_to(@line_item.cart, :notice => 'Line item was successfully created.') }
        format.xml  { render :xml => @line_item, :status => :created, :location => @line_item }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @line_item.errors, :status => :unprocessable_entity }
      end
    end
  end

  # PUT /line_items/1
  # PUT /line_items/1.xml
  def update
    @line_item = LineItem.find(params[:id])

    respond_to do |format|
      if @line_item.update_attributes(params[:line_item])
        format.html { redirect_to(@line_item, :notice => 'Line item was successfully updated.') }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @line_item.errors, :status => :unprocessable_entity }
      end
    end
  end

  # DELETE /line_items/1
  # DELETE /line_items/1.xml
  def destroy
    @line_item = LineItem.find(params[:id])
    @line_item.destroy

    respond_to do |format|
      format.html { redirect_to(line_items_url) }
      format.xml  { head :ok }
    end
  end
end

line_items_controller_test

require 'test_helper'

class LineItemsControllerTest < ActionController::TestCase
  setup do
    @line_item = line_items(:one)
  end

  test "should get index" do
    get :index
    assert_response :success
    assert_not_nil assigns(:line_items)
  end

  test "should get new" do
    get :new
    assert_response :success
  end
  test "should create line_item" do 
  assert_difference('LineItem.count') do 
    post :create, :product_id => products(:ruby).id 
  end 
  assert_redirected_to cart_path(LineItem.last.cart_id) 
  end 

  test "should show line_item" do
    get :show, :id => @line_item.to_param
    assert_response :success
  end

  test "should get edit" do
    get :edit, :id => @line_item.to_param
    assert_response :success
  end

  test "should update line_item" do
    put :update, :id => @line_item.to_param, :line_item => @line_item.attributes
    assert_redirected_to line_item_path(assigns(:line_item))
  end

  test "should destroy line_item" do
    assert_difference('LineItem.count', -1) do
      delete :destroy, :id => @line_item.to_param
    end

    assert_redirected_to line_items_path
  end
end