I am failing 3 tests and I have found numerous examples 
on here and 
on on the internet in general but I can't seem to find where I'm going wrong. Thanks for any help.
1) User pages signup with valid information edit page 
 Failure/Error: before { visit edit_user_path(user) }
 ActionView::Template::Error:
   undefined method `model_name' for NilClass:Class
 # ./app/views/users/edit.html.erb:6:in  `_app_views_users_edit_html_erb___4113112884365867193_70232486166220'
 # ./spec/requests/user_pages_spec.rb:96:in `block (5 levels) in <top (required)>'
2) User pages signup with valid information edit page 
 Failure/Error: before { visit edit_user_path(user) }
 ActionView::Template::Error:
   undefined method `model_name' for NilClass:Class
 # ./app/views/users/edit.html.erb:6:in `_app_views_users_edit_html_erb___4113112884365867193_70232486166220'
 # ./spec/requests/user_pages_spec.rb:96:in `block (5 levels) in <top (required)>'
3) User pages signup with valid information edit page 
 Failure/Error: before { visit edit_user_path(user) }
 ActionView::Template::Error:
   undefined method `model_name' for NilClass:Class
 # ./app/views/users/edit.html.erb:6:in `_app_views_users_edit_html_erb___4113112884365867193_70232486166220'
 # ./spec/requests/user_pages_spec.rb:96:in `block (5 levels) in <top (required)>'
Finished in 0.26515 seconds
3 examples, 3 failures
Failed examples:
rspec ./spec/requests/user_pages_spec.rb:100 # User pages signup with valid information edit page 
rspec ./spec/requests/user_pages_spec.rb:99 # User pages signup with valid information edit page 
rspec ./spec/requests/user_pages_spec.rb:101 # User pages signup with valid information edit page 
authentication_pages_spec.rb
    require 'spec_helper'
 describe "Authentication" do
 subject { page }
 describe "signin page" do
  before { visit signin_path }
  it { should have_selector('h1',    text: 'Sign in') }
  it { should have_selector('title', text: 'Sign in') }
end
describe "signin" do
before { visit signin_path }
describe "with invalid information" do
  before { click_button "Sign in" }
  it { should have_selector('title', text: 'Sign in') }
  it { should have_selector('div.alert.alert-error', text: 'Invalid') }
  describe "after visiting another page" do
    before { click_link "Home" }
    it { should_not have_selector('div.alert.alert-error') }
  end
end
describe "with valid information" do
  let(:user) { FactoryGirl.create(:user) }
  before do
    fill_in "Email", with: user.email
    fill_in "Password", with: user.password
    click_button "Sign in"
  end
  it { should have_selector('title', text: user.name) }
  it { should have_link('Profile', href: user_path(user)) }
  it { should have_link('Sign out', href: signout_path) }
  it { should_not have_link('Sign in', href: signin_path) }
  describe "followed by signout" do
    before { click_link "Sign out" }
    it { should have_link('Sign in') }
  end
 end
end
end  
Here is the users_controller:
    class UsersController < ApplicationController
 def show
   @user = User.find(params[:id])
 end
 def new
    @user = User.new
 end
 def create
     @user = User.new(params[:user])
    if @user.save
    sign_in @user
  flash[:success] = "Welcome to the Sample App!"
  redirect_to @user
else
  render 'new'
  end
 end
end
 def edit
     @user = User.find(params[:id])
 end      
edit.html.erb:
  <% provide(:title, "Edit user") %> 
  <h1>Update your profile</h1>
<div class="row">
 <div class="span6 offset3">
  <%= form_for(@user) do |f| %>
  <%= render 'shared/error_messages' %>
  <%= f.label :name %>
  <%= f.text_field :name %>
  <%= f.label :email %>
  <%= f.text_field :email %>
  <%= f.label :password %>
  <%= f.password_field :password %>
  <%= f.label :password_confirmation, "Confirm Password" %>
  <%= f.password_field :password_confirmation %>
   <%= f.submit "Save changes", class: "btn btn-large btn-primary" %>
  <% end %>
    <%= gravatar_for @user %>
  <a href="http://gravatar.com/emails">change</a>
 </div>
here is the user_pages_spec:
    require 'spec_helper'
describe "User pages" do
subject { page }
describe "profile page" do
let(:user) { FactoryGirl.create(:user) }
before { visit user_path(user) }
it { should have_selector('h1', text: user.name) }
it { should have_selector('title', text: user.name) }
end
describe "signup page" do
 before { visit signup_path }
it { should have_selector('h1', text: 'Sign up') }
it { should have_selector('title', text: full_title('Sign up')) }
end
describe "signup" do
before { visit signup_path }
describe "with invalid information" do
it "should not create a user" do
  expect { click_button "Create my account" }.not_to change(User, :count)
end
describe "error messages" do
  before { click_button "Create my account" }
  it { should have_selector('title', text: 'Sign up') }
  it { should have_content('error') }
 end
end
 describe "with valid information" do
  before do
    fill_in "Name", with: "Example User"
    fill_in "Email", with: "
[email protected]"
    fill_in "Password", with: "foobar"
    fill_in "Confirmation", with: "foobar"
 end
 it "should create a user" do
  expect do
    click_button "Create my account"
  end.to change(User, :count).by(1)
 end
 describe "after saving the user" do
  before { click_button "Create my account" }
  let(:user) { User.find_by_email('
[email protected]') }
  it { should have_selector('title', text: user.name) }
  it { should have_selector('div.alert.alert-success', text: 'Welcome') }
  it { should have_link('Sign out') }
 end
 end
end
 describe "signup page" do
 before { visit signup_path }
it { should have_selector('h1', text: 'Sign up') }
it { should have_selector('title', text: full_title('Sign up')) }
end
  describe "signup" do
before { visit signup_path }
let(:submit) { "Create my account" }
describe "with invalid information" do
it "should not create a user" do
  expect { click_button submit }.not_to change(User, :count)
 end
end
describe "with valid information" do
before do
  fill_in "Name", with: "Example User"
  fill_in "Email", with: "
[email protected]"
  fill_in "Password", with: "foobar"
  fill_in "Confirmation", with: "foobar"
end
it "should create a user" do
  expect { click_button submit }.to change(User, :count).by(1)
end
describe "edit" do
  let(:user) { FactoryGirl.create(:user) }
  before { visit edit_user_path(user) }
  describe "page" do
    it { should have_selector('h1', text: "Update your profile") }
    it { should have_selector('title', text: "Edit user") }
    it { should have_link('change', href: 'http://gravatar.com/emails') }
  end
  describe "with invalid information" do
    before { click_button "Save changes" }
    it { should have_content('error') }
    end
     end
     end
   end
 end
edit: users_controllers.rb was formatted incorrectly. It should look like this:    
class UsersController < ApplicationController
 def show
  @user = User.find(params[:id])
 end
def new
 @user = User.new
end
def create
 @user = User.new(params[:user])
 if @user.save
  sign_in @user
  flash[:success] = "Welcome to the Sample App!"
  redirect_to @user
else
  render 'new'
 end
end
def edit
  @user = User.find(params[:id])
 end 
end