add some logout and login

app/controllers/users_controller.rb

@@ -8,12 +8,18 @@ class UsersController < ApplicationController
   def create
     @user = User.new(user_params)
     if @user.save
+      log_in @user
       flash[:success] = "Welcome to the Sample App!"
       redirect_to @user
     else
       render 'new'
     end
   end
+
+  def destroy
+    log_out
+    redirect_to root_url
+  end
   private
   def user_params
     params.require(:user).permit(:name, :email, :password, :password_confirmation)

app/helpers/sessions_helper.rb

@@ -10,4 +10,9 @@ module SessionsHelper
 	def logged_in?
 		!current_user.nil?
 	end
+
+	def log_out
+    session.delete(:user_id)
+    @current_user = nil
+  end
 end

app/models/user.rb

@@ -9,4 +9,10 @@ class User < ActiveRecord::Base
 	validates :password, length: {minimum: 6}
 
 	has_secure_password
+
+	def User.digest(string)
+    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
+                                                  BCrypt::Engine.cost
+    BCrypt::Password.create(string, cost: cost)
+  end
 end

test/fixtures/users.yml

+michael:
+  name: Michael Example
+  email: michael@example.com
+  password_digest: <%= User.digest('password') %>
\ No newline at end of file

test/integration/users_login_test.rb

 require 'test_helper'
 
 class UsersLoginTest < ActionDispatch::IntegrationTest
+	def setup
+    @user = users(:michael)
+  end
+
 	test "login with invalid information" do
 		get login_path
 		assert_template 'sessions/new'
@@ -10,4 +14,34 @@ class UsersLoginTest < ActionDispatch::IntegrationTest
 		get root_path
 		assert flash.empty?
 	end
+
+	test "login with valid information" do
+    get login_path
+    post login_path, session: { email: @user.email, password: 'password' }
+    assert_redirected_to @user
+    follow_redirect!
+    assert_template 'users/show'
+    assert_select "a[href=?]", login_path, count: 0
+    assert_select "a[href=?]", logout_path
+    assert_select "a[href=?]", user_path(@user)
+  end
+
+  test "login with valid information followed by logout" do
+    get login_path
+    post login_path, session: { email: @user.email, password: 'password' }
+    assert is_logged_in?
+    assert_redirected_to @user
+    follow_redirect!
+    assert_template 'users/show'
+    assert_select "a[href=?]", login_path, count: 0
+    assert_select "a[href=?]", logout_path
+    assert_select "a[href=?]", user_path(@user)
+    delete logout_path
+    assert_not is_logged_in?
+    assert_redirected_to root_url
+    follow_redirect!
+    assert_select "a[href=?]", login_path
+    assert_select "a[href=?]", logout_path,      count: 0
+    assert_select "a[href=?]", user_path(@user), count: 0
+  end
 end

test/integration/users_signup_test.rb

@@ -18,5 +18,6 @@ class UsersSignupTest < ActionDispatch::IntegrationTest
     end
     assert_template 'users/show'
 		assert_not flash.empty?
+    assert is_logged_in?
   end
 end

test/test_helper.rb

@@ -8,4 +8,7 @@ class ActiveSupport::TestCase
   include ApplicationHelper
 
   # Add more helper methods to be used by all tests here...
+  def is_logged_in?
+    !session[:user_id].nil?
+  end
 end