介绍并扩展Fitnesse的测试模块化机制：Scenario

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。

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：

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:\git\FitnesseKit\fitnesse\src\fitnesse\testsystems\slim\tables下：

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

@Override

publicString substitute(String content)throwsSyntaxError {

for(Map.Entry 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{

thrownewSyntaxError(String.format("The argument %s is not an input to the scenario.", arg));

}

returncontent;

}

});

增加两行打印System.out.println：

@Override

publicString substitute(String content)throwsSyntaxError {

+ System.out.println("ScenarioTable.call.substitute <<<<<<<<<< content:"+ content);

for(Map.Entry 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{

thrownewSyntaxError(String.format("The argument %s is not an input to the scenario.", arg));

}

+ System.out.println("ScenarioTable.call.substitute >>>>>>>>>> content:"+ content);

returncontent;

}

在D:\git\FitnesseKit\fitnesse\src\fitnesse\testsystems\slim\tables\SlimTable.java的构造函数SlimTable中增加一行打印：

publicSlimTable(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:\git\FitnesseKit\fitnesse>ant compile

...

D:\git\FitnesseKit\fitnesse>ant run

再次运行刚刚失败的测试，现在看命令行打印：

<pre> [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]]
</pre>

再去运行一个没有被Scenario的封装的Script：

| check | login message | Bob logged in. |

| show | number of login attempts |

命令行打印如下内容：

1	[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("");
+       int trRightFirstIndex = content.indexOf("");
+       int trLeftSecondIndex = content.indexOf("", trLeftFirstIndex + 1);
+       int trRightSecondIndex = content.indexOf("", trRightFirstIndex + 1);
+       int scriptIndex = content.toLowerCase().indexOf("script");
+       if(scriptIndex > trLeftSecondIndex && scriptIndex < trRightSecondIndex) {
+         StringBuffer removeFirstTr = new StringBuffer();
+         removeFirstTr.append(content.substring(0, trLeftFirstIndex));
+         removeFirstTr.append(content.substring(trRightFirstIndex + "".length()));
+         content = removeFirstTr.toString();
+       }
		
        for (Map.Entry 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！