change borrow book logics,change to borrow book instance and manually choose which isntance

app/controllers/book_controller.rb

@@ -25,15 +25,17 @@ class BookController < ApplicationController
       redirect_to '/login', notice: 'You need login to do the action.'
       return
     end
-    book = Book.find_by_id params[:id]
-    if book.users.count <= book.current_borrowers.count
-      @msg = 'Sorry, there is no more book for lend.'
-    else
-      #book.borrowers << @current_user
-      @current_user.borrow book
-      @msg = 'Borrowed success.'
-    end
-    redirect_to :back, alert: @msg
+    #book = Book.find_by_id params[:id]
+    #if book.users.count <= book.current_borrowers.count
+    #  @msg = 'Sorry, there is no more book for lend.'
+    #else
+    #  #book.borrowers << @current_user
+    #  @current_user.borrow book
+    #  @msg = 'Borrowed success.'
+    #end
+    instance = BookInstance.find_by_id params[:instance_id].to_s
+    @current_user.borrow instance
+    redirect_to :back, alert: 'Borrow book success.'
   end
 
   def new

app/models/user.rb

@@ -18,8 +18,7 @@ class User < ActiveRecord::Base
     User.create name: name, avatar: avatar
   end
 
-  def borrow(book)
-    instance = book.available_instance
+  def borrow(instance)
     unless instance == nil
       borrow_records.create user_id: id, book_instance_id: instance.id, borrow_date: DateTime.now
     end

spec/models/book_instance_spec.rb

@@ -13,7 +13,7 @@ describe BookInstance do
   end
 
   it 'ensure when someone borrowed this book,borrowed? should return true' do
-    @user.borrow @book
+    @user.borrow @instance
     @instance.borrowed?.should == true
   end
 

spec/models/book_spec.rb

@@ -13,9 +13,9 @@ describe :Book do
 
     it 'when a book has two instances,ensure there is still one when another has been borrowed' do
       instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
-      @user.borrow @book
+      @user.borrow @instance
       @book.available_instance.should ==  instance_1
-      @user.borrow @book
+      @user.borrow instance_1
       @book.available_instance.should == nil
     end
   end
@@ -27,7 +27,7 @@ describe :Book do
 
     it 'ensure there should be one borrower' do
       instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
-      @user.borrow @book
+      @user.borrow @instance
       @book.current_borrowers.count.should == 1
       @book.current_borrowers[0].should == @user
     end
@@ -37,7 +37,7 @@ describe :Book do
     it 'ensure current_borrowers count equals total_borrowers count,when there isn"t some return books "' do
       instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
       @book.total_borrowers.count.should == 0
-      @user.borrow @book
+      @user.borrow instance_1
       @book.current_borrowers.count.should == 1
       @book.total_borrowers.count.should == 1
       @book.total_borrowers[0].name.should == @user.name
@@ -47,8 +47,8 @@ describe :Book do
     it 'ensure total_borrowers will count the user who returned the book' do
       instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
       user_1 = User.create name:'Tom'
-      @user.borrow @book
-      user_1.borrow @book
+      @user.borrow @instance
+      user_1.borrow instance_1
       @user.should_not == nil
       @user.return_book @instance
       @book.total_borrowers.count.should == 2
@@ -62,16 +62,16 @@ describe :Book do
      it 'ensure total available instance should be 1 after borrowed' do
        instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
        @book.total_available_instances.count.should == 2
-       @user.borrow @book
+       @user.borrow instance_1
        @book.total_available_instances.count.should == 1
      end
 
     it 'ensure total available instances should be two when someone return back his borrowed books' do
       instance_1 = BookInstance.create book_id: @book.id, user_id: @user.id
       @book.total_available_instances.count.should == 2
-      @user.borrow @book
+      @user.borrow instance_1
       @book.total_available_instances.count.should == 1
-      @user.return_book @instance
+      @user.return_book instance_1
       @book.total_available_instances.count.should == 2
     end
 

spec/models/user_spec.rb

@@ -7,13 +7,10 @@ describe :User do
   end
 
   describe 'user borrow a book' do
-    it 'ensure user can"t borrow a book, when there is no book instance' do
-       @user.borrow @book
-       @user.books.empty?.should be_true
-    end
+
     it 'ensure user can borrow a existed book'  do
       instance = BookInstance.create book_id: @book.id, user_id: @user.id
-      @user.borrow @book
+      @user.borrow instance
       @user.borrowed_and_not_returned_books.empty?.should be_false
       @user.borrowed_and_not_returned_books.count.should == 1
     end
@@ -23,7 +20,7 @@ describe :User do
       instance = BookInstance.create book_id: book_1.id, user_id: user_1.id
       instance_2 = BookInstance.create book_id: book_1.id, user_id: user_1.id
       user_1.borrowed_and_not_returned_books.count.should == 0
-      user_1.borrow book_1
+      user_1.borrow instance
       user_1.borrowed_and_not_returned_books.empty?.should be_false
       user_1.borrowed_and_not_returned_books.count.should == 1
 
@@ -34,7 +31,7 @@ describe :User do
   describe :borrowed_and_not_returned_books do
     it 'ensure return the book I borrowed and didn"t return back."' do
       instance = BookInstance.create book_id: @book.id, user_id: @user.id
-      @user.borrow @book
+      @user.borrow instance
       book_instances = @user.borrowed_and_not_returned_books
       book_instances.size.should == 1
       book_instances[0].should == instance
@@ -45,7 +42,7 @@ describe :User do
   describe :return_book do
     it 'ensure user return book,the borrowed books" count should decrease one"' do
       instance = BookInstance.create book_id: @book.id, user_id: @user.id
-      @user.borrow @book
+      @user.borrow instance
       @user.return_book instance
       @user.borrowed_and_not_returned_books.count.should == 0
     end