rspec语法积累

1 对象.should(_not) be_方法 ：应该（不应该）怎么样,方法的返回值为true/false
describe User do
	it "should be in any roles assigned to it" do 
	    user = User.new
		user.assign_role("assigned role")
		user.should be_in_role("assigned role")
	end

	it "should not be in any roles unassigned to it" do 
	    user = User.new
		user.assign_role("assigned role")
		user.should_not be_in_role("unassigned role")
	end

end

2 before/after(:each/:all) do end 
before(:all) do
  # 会在所有example运行前被调用一次
  end
  before do
  # 与before(:each)相同，会在每个example运行前被调用一次
  end
  after(:each) do
  # 会在每个example运行完后被调用一次
    @post.destroy unless @post.new_record?
  end
  after(:all) do
    # 会在所有examples运行完之后被调用一次
    Post.destroy_all
  end

实例：
describe Post do
  before(:each) do
    @post = Post.new(valid_post_hash) # grabs the hash below
  end
  it "should be valid" do
    @post.should be_valid
  end
  it "should not be valid without a title" do
    @post.title = ''
    @post.should_not be_valid
  end
  it "should not be valid without a body" do
    @post.body = ''
    @post.should_not be_valid
  end
  def valid_post_hash
    {:title => 'test', :body => 'test body'}
  end
end

3 走验证should be_valid
实例：
post.should be_valid

4 基本语法
Strings:

'foo'.should == 'foo'
'foo'.should === 'foo'
'foo'.should_not equal('foo')
''.should be_empty
'foo with bar'.should include('with')
'http://fr.ivolo.us'.should match(/http:\/\/.+/i)
nil.should be_nil

Numbers:

100.should < 200
200.should >= 100
(200 - 100).should == 100

# (100 - 80) is less than 21
100.should be_close(80,21)

Arrays:

[1,2,3].should have(3).items
[].should be_empty
[1,2,3].should include(2)

Hashes:

{}.should be_empty
{:post => {:title => 'test'}}.should have_key(:post)
{:post => {:title => 'test'}}.should_not have_key(:title)
false.should be_false
true.should be_true

Records:

# assuming @post = Post.new(:title => 'test')
@post.should be_instance_of(Post)
@post.should respond_to(:title)

5 有关数据库的操作
实例：
def comment
  @post = Post.find(params[:id])
  @comment = Comment.new(params[:comment])
  respond_to do |format|
    if @comment.save && @post.comments.concat(@comment)
      flash[:notice] = 'Comment was successfully updated.'
      format.html { redirect_to post_path(@blogger, @post) }
      format.xml { head :o k }
    else
      flash[:notice] = 'Error saving comment.'
      format.html { redirect_to post_path(@blogger, @post) }
      format.xml { render :x ml => @comment.errors.to_xml }
    end
  end
end
我需要确保我能够对帖子发布评论：

it "should add comments to the post" do
  post = posts(:one)
  comment_count = post.comments.size
  post :comment, :id => 1, :comment => {:title => 'test', :body => 'very nice!'}
  post.reload
  post.comments.size.should == comment_count + 1
  flash[:notice].should match(/success/i)
  response.should redirect_to(posts_path(@blogger, @post))
end

看起来不错？但这个测试例实际测试了许多不该它来测试的东西，它应该只测试action，但是它却连同model也一并测试了，并且它还依赖于fixtures。

我们可以使用一个mock object来代替真是的post对象：

post = mock_model(Post)

现在我们需要关注comment的第一行：

@post = Post.find(params[:id])

我希望这一行在测试时得到执行，但是不用测试，我也知道这行代码肯定是工作正常的，因此，我现在要做的就是让这行代码返回我在上面创建的那个mock object：

Post.should_receive(:find).and_return(post)

或者这样：

Post.stub!(:find).and_return(post)

但 是请注意，should_receive和stub!虽然都可以让Post.find返回我的mock object，但是他们的区别却是巨大的，如果我调用了stub!，但是却没有调用Post.find，stub!不会抱怨什么，因为它是个老实人，但是 should_receive就不用，如果我告诉should_receive我会调用Post.find，但却没调用，那问题就来了，它会抱怨为何我不 守信用，并抛出一个异常来警告我。

但是跟在他们后面的and_return的作用却是完全相同的，它让你mock或者stub的方法返回你传递给它的任何参数。

接下来，我需要对comment做同样的事情：

comment = mock_model(Comment)
Comment.should_receive(:new).with({:title => 'comment title', :body => 'comment body'}).and_return(comment)

接下来我需要关注这条语句：

if @comment.save && @post.comments.concat(@comment)

同上面一样：

comment.should_receive(:save).and_return(true)
post.comments.should_receive(:concat).and_return(comment)

下面我需要测试flash及redirect：

flash[:notice].should match(/success/i)
response.should redirect_to(posts_path(blogger, post))

现在，还剩下最后一件事情：这个action必须使用blogger变量来进行重定向，这里我使用instance_variable_set来完成这个工作：

blogger = mock_model(User)
@controller.instance_variable_set(:@blogger, blogger)

基本就是这样，下面是将部分代码放入before中的完整代码：

describe PostsController, "comment", :behaviour_type => :controller, do
  before do
    @post = mock_model(Post)
    Post.should_receive(:find).and_return(@post)
    @comment = mock_model(Comment)
    Comment.should_receive(:new).with.({:title => 'comment title', :body => 'comment body'}).and_return(@comment)
    @blogger = mock_model(User)
    @controller.instance_variable_set(:@blogger, @blogger)
  end
  it "should add comments to the post" do
    @comment.should_receive(:save).and_return(true)
    @post.comments.should_receive(:concat).and_return(@comment)
    post :comment, :id => @post.id, :comment => {:title => 'comment title', :body => 'comment body'}
    flash[:notice].should match(/success/i)
    response.should redirect_to(posts_path(@blogger, @post))
  end
end