在前面我们编写并进行了一些单元测试和功能测试，现在，我们的客户突然要求添加一个功能：系统的每个用户都可以对商品进行查询。
现在，我们来考虑一下查询功能的测试，应该由哪个controller来控制查询操作呢？用户和管理员都可以进行查询操作，我们可以在store_controller.rb或者admin_controller.rb中添加一个search()的Action，但是这里我们添加一个SearchController，并且含有一个方法search。在rails命令行执行命令：
depot>ruby script/generate controller Search search
我们看到，在app/controllers和test/functional目录下已经生成了对应的文件。但是现在我们并不关心SearchController的search方法的实现，我们关心的是在测试时我们所期望看到的结果。现在添加测试代码，在test/functional/search_controller_test.rb中添加test_search方法：
我们首先想到的是调用search的Action，然后判断是否得到了响应：
get :search, :title => "Pragmatic Version Control"
assert_response :success
根据之前的草图，我们应该在页面上显示一个flash信息，所以我们要判断flash信息的文本，以及是否显示了正确的页面:
assert_equal "Found 1 product(s).", flash[:notice]
assert_template "search/results"
然后我们想要判断查询所得到的商品信息：
products = assigns(:products)
assert_not_nil products
assert_equal 1, products.size
assert_equal "Pragmatic Version Control", products[0].title
我们还想判断用来显示查询结果的页面的一些内容，我们查询到的商品会作为列表在页面上显示，我们使用catelog视图相同的css样式：
assert_tag :tag => "div",
:attributes => { :class => "results" },
:children => { :count => 1,
:only => { :tag => "div",
:attributes => { :class => "catalogentry" }}}
下面是完整的测试方法：
def test_search
get :search, :title => "Pragmatic Version Control"
assert_response :success
assert_equal "Found 1 product(s).", flash[:notice]
assert_template "search/results"
products = assigns(:products)
assert_not_nil products
assert_equal 1, products.size
assert_equal "Pragmatic Version Control", products[0].title
assert_tag :tag => "div",
:attributes => { :class => "results" },
:children => { :count => 1,
:only => { :tag => "div",
:attributes => { :class => "catalogentry" }}}
end
现在我们来运行测试：ruby test/functional/search_controller_test.rb
不出意外，会得到下面的结果：
test_search(SearchControllerTest) [test/functional/search_controller_test.rb:17]:
<"Found 1 product(s)."> expected but was
<nil>.
1 tests, 2 assertions, 1 failures, 0 errors
因为我们还没有设置flash的内容，进一步说，我们还没有实现search这个Action。怎样实现，书上给留了个作业。OK，那我们就自己来一步步实现search的Action。
1. 给search方法添加内容：
@products = Product.find(:all,:conditions=>['title=?',params[:title]])
if not @products.nil?
flash[:notice] = sprintf('Found %d product(s).',@products.size)
end
render(:action=>'results')现在运行测试，结果如下：
----------------------------------------------------------------------------
1) Failure:
test_search(SearchControllerTest)
[Z:/study/ruby/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack……
Z:/study/ruby/InstantRails/ruby/lib/ruby/gems/1.8/gems/actionpack……
test/functional/search_controller_test.rb:19:in `test_search']:
expecting <"search/results"> but rendering with <"search/search">
1 tests, 3 assertions, 1 failures, 0 errors
----------------------------------------------------------------------------
2. 这次轮到assert_template "search/results"断言出错了，是因为我们还没有results这个View，我们在view目录下添加一个results.rhmtl文件，在search_controller.rb文件中添加一个results的空方法：
def results
end
还要在search方法中添加一句：render("search/results")，然后再运行测试，结果如下：
----------------------------------------------------------------------------
Finished in 0.125 seconds.
1) Failure:
test_search(SearchControllerTest)
[Z:/study/ruby/InstantRails/ruby/lib/ruby/gems/1.8/gems/…… Z:/study/ruby/InstantRails/ruby/lib/ruby/gems/1.8/gems/……
expected tag, but no tag found matching {:attributes=>{:class=>"results"}, :tag=>"div",
"<h1>Search#results</h1>\n<p>Find me in app/views/search/results.rhtml</p>\n".
<nil> is not true.
----------------------------------------------------------------------------
3. 现在可以看到，就只有最后一个断言assert_tag没有通过了，这个断言是对页面上的元素进行判断的，所以我们来实现results页面。仔细看看断言的内容，我们就知道只要在results.rhtml里添加两个div就可以了，下面是results.rhtml的完整内容：
<h1>Search#results</h1>
<p>Find me in app/views/search/results.rhtml</p>
<div class="results">
<div class = "catalogentry">
</div>
</div>
保存，然后再运行测试，激动人心的时刻来临了，所有的断言都通过了！测试OK了，下面是结果：
----------------------------------------------------------
DEPRECATION WARNING: You called render('search/result……
t Z:/study/ruby/InstantRails/ruby/lib/ruby/gems/1.8/g……
Finished in 0.094 seconds.
1 tests, 7 assertions, 0 failures, 0 errors
----------------------------------------------------------
4. 在实现search.rhtml和results.rhtml的时候，我碰到了一些问题，用测试用例都可以选出数据来，但是通过页面就怎么也不行了，把log里的sql贴出来到phpMyAdmin里执行，也能选出数据，真不知道是怎么回事，自己对rails的理解还不深，自己胡乱写了这些代码，先把代码都帖出来，等自己对rails有更深入的理解的时候看能不能找到问题。同时也请高人指点
search_controller_test.rb:
require File.dirname(__FILE__) + '/../test_helper'
require 'search_controller'
# Re-raise errors caught by the controller.
class SearchController; def rescue_action(e) raise e end; end
class SearchControllerTest < Test::Unit::TestCase
fixtures :products
def setup
@controller = SearchController.new
@request = ActionController::TestRequest.new
@response = ActionController::TestResponse.new
end
def test_search
get :search, :title => "Pragmatic Version Control"
assert_response :success
assert_equal "Found 1 product(s).", flash[:notice]
assert_template "search/results"
products = assigns(:products)
assert_not_nil products
assert_equal 1, products.size
assert_equal "Pragmatic Version Control", products[0].title
assert_tag :tag => "div",
:attributes => { :class => "results" },
:children => { :count => 1,
:only => { :tag => "div",
:attributes => { :class => "catalogentry" }}}
end
end
search_controller.rb
class SearchController < ApplicationController
def search
print(params[:title])
@products = Product.find(:all,:conditions=>['title=?',params[:title]])
if not @products.nil?
flash[:notice] = sprintf('Found %d product(s).',@products.size)
end
print(flash[:notice])
#redirect_to(:action=>'results')
render(:action=>'results')
end
def results
end
def index
end
end
Views下有三个文件：index.rhtml，results.rhtml，search.rhtml
index.rhtml：
<html>
<%= form_tag(:action=>'search',:id=>@products) %>
<table>
<tr>
<td>Book title:</td>
<td><%=text_field("title","")%></td>
</tr>
<tr>
<td><input type="submit" value="SEARCH" /></td>
</tr>
</table>
<%= end_form_tag %>
</html>
results.rhtml：
<h1>Search#results</h1>
<p>Find me in app/views/search/results.rhtml</p>
<div class="results">
<div class = "catalogentry">
<table cellpadding="10" cellspacing="0">
<tr class="carttitle">
<td >title</td>
<td >description</td>
<td >price</td>
</tr>
<%
printf("result:%d",@products.size)
for product in @products
-%>
<tr>
<td><%= product.title %></td>
<td><%= product.description%></td>
<td align="right"><%= fmt_dollars(product.price) %></td>
</tr>
<% end %>
</table>
</div>
</div>
search.rhtml：
<html></html>