介绍并扩展Fitnesse的测试模块化机制：ScenarioTable

摘要：在验收测试框架Fitneese中，使用Scenario可以把最常用的测试步骤封装起来，从而达到模块化定义Fitnesse测试用例的能力。但Scenario仅限于封装Script测试步骤，Script实例要先创建，然后才能调用；Scenario也不能封装Table。本文后半部分展示修改Fitneese代码，扩展Scenario的封装范围。

首先普及一下概念，什么是Fitnesse，听一听.NET版Cucumber的创始人Aslak Hellesøy谈Fitnesse与Cucumber对比：

FIT/Fitnesse和Cucumber都执行高级语言编写的验收测试。FIT仅识别HTML，Fitnesse则通过提供Wiki语法来简化编写测试的过程。在FIT/Fitnesse当中，所有的测试都以表格的形式呈现。
FitNesse比Cucumber的优势在于Wiki支持。

原文链接：http://www.infoq.com/cn/news/2009/11/interview-cucumber-for-dotnet

1.Scenario是什么

Fitneese的SliM UserGuide中介绍了 Scenario

原文是这么介绍Scenario的：

A Scenario table is a table that can be called from other tables; namely Script Table and Decision Table.

The format of a Scenario table is the same as the format of a Script Table, but with a few differences. You can see a Scenario table in action here.

Scenario是一种Table，可以被Script Table 和 Decision Table调用。

由此很多人都对Scenario报了很大的期望，希望能用Scenario模块化封装测试步骤。

2.Scenario能力展示

下面是我结合Script示例和Scenario示例写的一个Scenario演示用例：

wiki文本：

!define TEST_SYSTEM {slim}
!path classes

|import|
|fitnesse.slim.test|

!4 定义scenario checkLogin: 登录并检查结果
| scenario | checkLogin | u || p || ensure || logged |
| @{ensure} | login with username | @{u} | and password | @{p} |
| check @{logged} | login message | @{u} logged in. |
| show | number of login attempts |

!4 创建script实例，后面调用scenario都是针对这个实例
| script | login dialog driver | Bob | xyzzy |

!4 Invoking a scenario from a !-DecisionTable-!
| checkLogin |
| u | p | ensure | logged |
| Bob | xyzzy | ensure |  |
| Bob | zzyxx | reject | not |
| Cat | xyzzy | reject | not |

!4 Invoking a scenario from a !-ScriptTable-!
| script |
| checkLogin | Bob || zzyxx || reject || not |
| checkLogin | Bob || xyzzy || ensure ||  |

!4 script原示例
| script | login dialog driver | Bob | xyzzy |
| login with username | Bob | and password | xyzzy |
| check | login message | Bob logged in. |
| reject | login with username | Bob | and password | bad password |
| check | login message | Bob not logged in. |
| check not | login message | Bob logged in. |
| ensure | login with username | Bob | and password | xyzzy |
| note | this is a comment |
| show | number of login attempts |
| $symbol= | login message |

The fixture for this table is:{{{public class LoginDialogDriver {
  private String userName;
  private String password;
  private String message;
  private int loginAttempts;

  public LoginDialogDriver(String userName, String password) {
    this.userName = userName;
    this.password = password;
  }

  public boolean loginWithUsernameAndPassword(String userName, String password) {
    loginAttempts++;
    boolean result = this.userName.equals(userName) && this.password.equals(password);
    if (result)
      message = String.format("%s logged in.", this.userName);
    else
      message = String.format("%s not logged in.", this.userName);
    return result;
  }

  public String loginMessage() {
    return message;
  }

  public int numberOfLoginAttempts() {
    return loginAttempts;
  }
} }}}

测试用例页面：

点击Test执行后：

展开DecisionTable调用Scenario的测试结果：

展开ScriptTable调用Scenario的测试结果：

至此，我们看到Scenario可以把Script步骤封装起来，取个模块名，然后使用DecisionTable或ScriptTable调用。

3.Scenario的局限

请注意调用Scenario前的这一行：

目的是在调用Scenario前先创建好Script实例。

如果去掉这一句，再执行，是这样的结果：

再尝试一下，把创建Script实例的语句塞到Scenario中：

!4 定义scenario checkLogin: 登录并检查结果
| scenario | checkLogin | u || p || ensure || logged |
| script | login dialog driver | Bob | xyzzy |   <--这是新加的创建Script实例的语句
| @{ensure} | login with username | @{u} | and password | @{p} |
| check @{logged} | login message | @{u} logged in. |
| show | number of login attempts |

保存后执行测试：

4.不满意怎么办？

我还想使用Scenario封装TableTable，比如RestFixture定义的TableTable，
国外最著名的软件开发问答网站stackoverflow.com也在问：
Can I make a scenario of RestFixture table in fitnesse?, or is there another way to make reusable components?

我准备修改Fitneese代码，使得Scenario能直接封装ScriptTable和TableTable，请往下看……

5.修改ScenarioTable.java，使Scenario能直接封装ScriptTable

Scenario的源代码在目录D:gitFitnesseKitfitnessesrcfitnesse estsystemsslim ables下：

打开ScenarioTable.java后，关键代码是Scenario的参数@xxx是怎么替换的:

      @Override
      public String substitute(String content) throws SyntaxError {
        for (Map.Entry<String, String> scenarioArgument : scenarioArguments.entrySet()) {
          String arg = scenarioArgument.getKey();
          if (getInputs().contains(arg)) {
            String argument = scenarioArguments.get(arg);
            content = StringUtil.replaceAll(content, "@" + arg, argument);
            content = StringUtil.replaceAll(content, "@{" + arg + "}", argument);
          } else {
            throw new SyntaxError(String.format("The argument %s is not an input to the scenario.", arg));
          }
        }
        return content;
      }
    });

增加两行打印System.out.println：

      @Override
      public String substitute(String content) throws SyntaxError {
+      System.out.println("ScenarioTable.call.substitute <<<<<<<<<< content:" + content);
        for (Map.Entry<String, String> scenarioArgument : scenarioArguments.entrySet()) {
          String arg = scenarioArgument.getKey();
          if (getInputs().contains(arg)) {
            String argument = scenarioArguments.get(arg);
            content = StringUtil.replaceAll(content, "@" + arg, argument);
            content = StringUtil.replaceAll(content, "@{" + arg + "}", argument);
          } else {
            throw new SyntaxError(String.format("The argument %s is not an input to the scenario.", arg));
          }
        }
+      System.out.println("ScenarioTable.call.substitute >>>>>>>>>> content:" + content);
        return content;
      }

在D:gitFitnesseKitfitnessesrcfitnesse estsystemsslim ablesSlimTable.java的构造函数SlimTable中增加一行打印：

      public SlimTable(Table table, String id, SlimTestContext testContext) {
+      System.out.println("SlimTable.SlimTable table:"+table);
        this.id = id;
        this.table = table;
        this.testContext = testContext;
        tableName = getTableType() + "_" + id;
      }

目的是查看每次启动的测试Table，比如一次import，一次ScriptTable，一次DecisionTable，一次TableTable，等等。

使用命令ant compile重新编译Fitnesse，并输入ant run重新启动Fitneese：
D:gitFitnesseKitfitnesse>ant compile
...
D:gitFitnesseKitfitnesse>ant run

再次运行刚刚失败的测试，现在看命令行打印：

 [java] ScenarioTable.call.substitute <<<<<<<<<< content:<table>
 [java]     <tr>
 [java]             <td>scenario</td>
 [java]             <td>checkLogin</td>
 [java]             <td>u</td>
 [java]             <td></td>
 [java]             <td>p</td>
 [java]             <td></td>
 [java]             <td>ensure</td>
 [java]             <td></td>
 [java]             <td>logged</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>Script</td>
 [java]             <td>login dialog driver</td>
 [java]             <td>Bob</td>
 [java]             <td colspan="6">xyzzy</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>@{ensure}</td>
 [java]             <td>login with username</td>
 [java]             <td>@{u}</td>
 [java]             <td>and password</td>
 [java]             <td colspan="5">@{p}</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>check @{logged}</td>
 [java]             <td>login message</td>
 [java]             <td colspan="7">@{u} logged in.</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>show</td>
 [java]             <td colspan="8">number of login attempts</td>
 [java]     </tr>
 [java] </table>
 [java] ScenarioTable.call.substitute >>>>>>>>>> content:<table>
 [java]     <tr>
 [java]             <td>scenario</td>
 [java]             <td>checkLogin</td>
 [java]             <td>u</td>
 [java]             <td></td>
 [java]             <td>p</td>
 [java]             <td></td>
 [java]             <td>ensure</td>
 [java]             <td></td>
 [java]             <td>logged</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>Script</td>
 [java]             <td>login dialog driver</td>
 [java]             <td>Bob</td>
 [java]             <td colspan="6">xyzzy</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>ensure</td>
 [java]             <td>login with username</td>
 [java]             <td>Bob</td>
 [java]             <td>and password</td>
 [java]             <td colspan="5">xyzzy</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>check </td>
 [java]             <td>login message</td>
 [java]             <td colspan="7">Bob logged in.</td>
 [java]     </tr>
 [java]     <tr>
 [java]             <td>show</td>
 [java]             <td colspan="8">number of login attempts</td>
 [java]     </tr>
 [java] </table>
 [java] SlimTable.SlimTable table:[[scenario,checkLogin,u,,p,,ensure,,logged],[Script, login dialog driver, Bob, xyzzy], [ensure, login with username, Bob, and password, xyzzy], [check , login message, Bob logged in.], [show, number of login attempts]]

再去运行一个没有被Scenario的封装的Script：

| Script | login dialog driver | Bob | xyzzy |
| ensure | login with username | Bob | and password | xyzzy |
| check | login message | Bob logged in. |
| show | number of login attempts |

命令行打印如下内容：

 [java] SlimTable.SlimTable table:[[Script, login dialog driver, Bob, xyzzy], [ensure, login with username, Bob, and password, xyzzy], [check , login message, Bob logged in.], [show, number of login attempts]]

对比一下两种运行的打印：

[java] SlimTable.SlimTable table:[[scenario,checkLogin,u,,p,,ensure,,logged],[Script, login dialog driver, Bob, xyzzy], [ensure, login with username, Bob, and password, xyzzy], [check , login message, Bob logged in.], [show, number of login attempts]]

[java] SlimTable.SlimTable table:[[Script, login dialog driver, Bob, xyzzy], [ensure, login with username, Bob, and password, xyzzy], [check , login message, Bob logged in.], [show, number of login attempts]]

只要想办法在运行封装时，去掉[scenario,checkLogin,u,,p,,ensure,,logged],，说不定就可以了。

接下去，修改substitute函数：

      public String substitute(String content) throws SyntaxError {
        System.out.println("ScenarioTable.call.substitute <<<<<<<<<< content:" + content);
+       int trLeftFirstIndex = content.indexOf("<tr>");
+       int trRightFirstIndex = content.indexOf("</tr>");
+       int trLeftSecondIndex = content.indexOf("<tr>", trLeftFirstIndex + 1);
+       int trRightSecondIndex = content.indexOf("</tr>", trRightFirstIndex + 1);
+       int scriptIndex = content.toLowerCase().indexOf("<td>script</td>");
+       if(scriptIndex > trLeftSecondIndex && scriptIndex < trRightSecondIndex) {
+         StringBuffer removeFirstTr = new StringBuffer();
+         removeFirstTr.append(content.substring(0, trLeftFirstIndex));
+         removeFirstTr.append(content.substring(trRightFirstIndex + "</tr>".length()));
+         content = removeFirstTr.toString();
+       }
        
        for (Map.Entry<String, String> scenarioArgument : scenarioArguments.entrySet()) {
          String arg = scenarioArgument.getKey();
          if (getInputs().contains(arg)) {
            String argument = scenarioArguments.get(arg);
            content = StringUtil.replaceAll(content, "@" + arg, argument);
            content = StringUtil.replaceAll(content, "@{" + arg + "}", argument);
          } else {
            throw new SyntaxError(String.format("The argument %s is not an input to the scenario.", arg));
          }
        }
        System.out.println("ScenarioTable.call.substitute >>>>>>>>>> content:" + content);
        return content;
      }        

再次编译，运行Fitneese：

耶，一击中的！

具体的代码在 git.oschina.net

6.尝试用Scenario封装TableTable

因为RestFixture是用TableTable实现的，所以我还想用Scenario封装TableTable，以便在使用RestFixture时，可以模块化组织测试步骤。

首先看一个TableTable例子:

!define TEST_SYSTEM {slim}

!path D:gitFitnesseKitRestFixture	argetdependencies*
!path D:gitFitnesseKitRestFixture	argetclasses
!path D:gitFitnesseKitRestFixtureextraslf4j-simple-1.6.6.jar

| import |
| smartrics.rest.fitnesse.fixture |

获取开始时间
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | begin | js | (new Date()).getTime() | |

调用某个服务，这里用 sleep 5秒 模拟
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | sleepMiliSeconds | js | {{{
var start = (new Date()).getTime();
var now;
do {
  now = (new Date()).getTime();
} while(now - start < 5000);
now - start }}} | |

获取结束时间
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | end | js | (new Date()).getTime() | |

打印调用服务所花时间
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | spendSeconds | js | (%end% - %begin%) / 1000 | |

测试结果是这样的：

本测试用例的主要目的是检查调用某个服务所花的时间，本例子是5秒。

接下去我想把上面的获取当前时间，调用服务，计算所花时间都写成Scenario，然后用Script调用Scenario，使测试步骤具有良好的可读性：

!define TEST_SYSTEM {slim}

!path D:gitFitnesseKitRestFixture	argetdependencies*
!path D:gitFitnesseKitRestFixture	argetclasses
!path D:gitFitnesseKitRestFixtureextraslf4j-simple-1.6.6.jar

| import |
| smartrics.rest.fitnesse.fixture |

获取当前时间
| scenario |  getTime | _t |
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | @{_t} | js | (new Date()).getTime() | |

计算所花时间
| scenario |  spendSeconds | _s || beginTime || endTime |
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | @{_s} | js | (@{endTime} - @{beginTime}) / 1000 | |

调用某个服务，用sleep模拟
| scenario |  sleep | s |
| Table:Rest Fixture | http://localhost:${FITNESSE_PORT} |
| let | sleepMiliSeconds | js | {{{
var start = (new Date()).getTime();
do {
  var now = (new Date()).getTime();
} while(now - start < @{s} * 1000);
now - start }}} | |

打印调用某个服务所花时间
| script |
| getTime | begin |
| sleep | 5 |
| getTime | end |
| spendSeconds | spend || %begin% || %end% |

测试结果是这样的：

保存内容是The instance scriptTableActor. does not exist，意思为从已定义的script中找不到。

修改ScenarioTable.java后，测试结果：

ScenarioTable.java的主要修改内容：

请到git.oschina.net具体查看。