Rails 集成测试写法的变化过程 Rails测试方法合集

在 http://giantrobots.thoughtbot.com逛的时候看到的，小夜觉得有些东西还是能说明问题的，就抄回来了。
Productivity and happiness.这是Ruby和Rails升起的原因，也是integration testing能够持续变化的原因。当然，原文作者客气的说，这只是个人理解并没有科学证据。

2006

使用如下方法

引用

get, post, follow_redirect!, xml_http_request, status, path, and open_session

通过assert_equal来验证。通常写法如下：

class ExampleTest < ActionController::IntegrationTest
  def test_login
    get "/login"
    assert_equal 200, status

    post "/login",
      :username => people(:jamis).username,
      :password => people(:jamis).password
    follow_redirect!

    assert_equal 200, status
    assert_equal "/home", path
  end
end

2007

RSpec引入所谓行为驱动，就是故事模式如下：

Scenario "Root user" do
  Given "a user named", "admin"
  And "a company named", "Company1"
  And "a company named", "Company2"

  And "the user has the role", "root" do |role|
    @user.update_attribute :role, role
  end
  And "logged in as", "admin"

  When "visiting", "/"

  Then "viewer should see", "main/root_home"
  And  "page should show company named", "Company1" do |name|
    response.should have_text(/#{name}/)
  end
  And  "page should show company named", "Company2"
end

Webrat在这个时候模拟浏览器行为用于测试网页。 DSL通过

引用

click_link, fill_in, and click_button

Webrat可以和 配合使用 Nokogiri测试网页，使用XPath 和 CSS selectors来验证HTML的返回。
通常这样写：

def test_sign_up
  visits "/"
  clicks_link "Sign up"
  fills_in "Email", :with => "[email protected]"
  select "Free account"
  clicks_button "Register"
  ...
end

2008

Merb推荐使用request方法。而这也比dispatch_to更容易。通常会用到

引用

be_successful and redirect_to

这时 Cucumber取代讲故事的Story Runner模式。如下：

Feature: Addition
  In order to avoid silly mistakes
  As a math idiot 
  I want to be told the sum of two numbers

  Scenario: Add two numbers
    Given I have entered 2 into the calculator
    And I have entered 2 into the calculator
    When I press add
    Then the result should be 4 on the screen

Given /^I signed up with "(.*)\/(.*)"$/ do |email, password|
  user = Factory :user,
    :email                 => email,
    :password              => password,
    :password_confirmation => password
end 

2009

Integration testing 成为主流

Rack::Test通过给测试框架提供一个公用的接口来和Rack应用交互。

引用

Rack::Test pays homage to the frameworks before it, using methods that match the HTTP verbs: get, post, put, and delete, head) and adding request (Merb) and follow_redirect! (Rails). It also handles HTTP authentication and stores requests and responses in last_request and last_response.

示例如下：

class HelloWorldTest < Test::Unit::TestCase
  include Rack::Test::Methods

  def app
    [color=red]Sinatra[/color]::Application
  end

  def test_it_says_hello_world
    get '/'
    assert last_response.ok?
    assert_equal 'Hello World', last_response.body
  end

  def test_it_says_hello_to_a_person
    get '/', :name => 'Simon'
    assert last_response.body.include?('Simon')
  end
end

Cucumber and Webrat 也得到发展

Feature "A Tomatoist does a pomodoro" do
  Story <<-eos
  In order to perform a focused unit of work
  As a Tomatoist
  I want to start a pomodoro
  eos

  Scenario "Starting a pomodoro" do
    When "I go to the home page" do
      executes { visit '/' }

      Then "I should be sent to a new session" do
        current_url.should =~ /\/\w{3,}/
      end

      And "I should see an unstarted timer" do
        response.should have_tag('#timer .countdown_row','00:00')
      end

      When "I click the pomodoro button" do
        executes do
          @session_url = current_url
          click_button 'Pomodoro'
        end

        Then "I should be on my session's page" do
          current_url.should == @session_url
        end

        And "my timer history should show the current pomdoro" do
          response.should have_tag('#history ul li', /Pomodoro/, 1)
        end
      end
    end
  end
end

Coulda同样使用定义语言通过 Webrat或者其他库来模拟浏览器行为如下：

Feature "Painfully obvious" do
  in_order_to "demonstrate a simple test"
  as_a "coulda developer"
  i_want_to "provide a straight-forward scenario"

  Scenario "Describing something obvious" do
    Given "something without a value" do
      @no_value = nil
    end

    When "I give it a value" do
      @no_value = true
    end

    Then "it should have a value" do
      assert(@no_value)
    end
  end
end

Given同样

class StackBehavior < Given::TestCase
  Invariant { expect(@stack.depth) >= 0 }
  Invariant { expect(@stack.empty?) == (@stack.depth == 0) }

  def empty_stack
    @stack = Stack.new
  end

  Given(:empty_stack) do
    Then { expect(@stack.depth) == 0 }

    When { @stack.push(:an_item) }
    Then { expect(@stack.depth) == 1 }
    Then { expect(@stack.top) == :an_item }

    When { @stack.pop }
    FailsWith(Stack::UsageError)
    Then { expect(exception.message) =~ /empty/ }
  end
end

引用

I write about 50 lines of horrible hacks. It brings the Given/When/Then DSL to Test::Unit. It relies on Webrat and Rack::Test to simulate the browser and theoretically work for all Rack apps (only tested on Sinatra). I keep the nesting totally flat, as is my style. It looks like this:

Feature 'Shorten URL' do
  Given 'I am on the homepage' do
    visit '/'
  end

  When 'I submit http://example.com' do
    fill_in      'url', :with => 'http://example.com'
    click_button 'shorten'
  end

  Then 'I should see a short link' do
    assert_have_selector 'a#short'
  end

  When 'I follow the short link' do
    click_link 'short'
  end

  Then 'I should be on http://example.com' do
    assert_equal 'http://example.com', current_url
  end
end

原文还有一些解释，没太注意，然而，从这样一个Rails的测试进化过程，还是能够看到一些东西。