unittest如何在循环遍历一条用例时生成多个测试结果

引用自:http://blog.csdn.net/kaku21/article/details/42124593

参考网址：http://programmaticallyspeaking.com/test-data-provider-using-python-metaclass.html

使用TestNG进行测试的时候，允许使用外部数据源来驱动测试方法的执行，举个例子：

我们有一个测试方法，而这个测试方法对应有10条测试数据，如果我们在测试方法中使用循环遍历这十条数据的话，很可能出现的问题是：

1.测试中的断言 assert 遇到一条数据执行结果错误时，退出测试方法

2.剩余的数据无法继续执行，产生的数据报告不完整

解决上述问题的方法，利用TestNG的dataprodvider在测试类中获取外部数据，然后传给测试方法，这样做到每一条数据驱动一次测试方法的执行，测试方法按数据量自动产生方法序号，报告测试结果。当某一条数据执行结果错误的时候，该方法对应的产生一次失败信息，但不影响下一条数据的执行。

在测试报告中，看到的是某一个方法，然后产生了多少条报告。

关于TestNG数据驱动的详情可以参考 http://testng.org/doc/documentation-main.html#parameters-dataproviders

我们要说的是，在python的unittest中没有类似的方法，当我们需要遍历测试数据的时候怎样更好的去查看结果生成报告呢？

目前我没有找到比较好的第三方组件，唯一的方式是自己来改写，参看下面的代码

<pre><span class="kn">import</span> <span class="nn">unittest</span>  
  
<span class="k">class</span> <span class="nc">DataProviderSupport</span><span class="p">(</span><span class="nb">type</span><span class="p">):</span>  
    <span class="k">def</span> <span class="nf">__new__</span><span class="p">(</span><span class="n">meta</span><span class="p">,</span> <span class="n">classname</span><span class="p">,</span> <span class="n">bases</span><span class="p">,</span> <span class="n">classDict</span><span class="p">):</span>  
        <span class="c"># method for creating our test methods</span>  
        <span class="k">def</span> <span class="nf">create_test_method</span><span class="p">(</span><span class="n">testFunc</span><span class="p">,</span> <span class="n">args</span><span class="p">):</span>  
            <span class="k">return</span> <span class="k">lambda</span> <span class="bp">self</span><span class="p">:</span> <span class="n">testFunc</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">)</span>  
  
        <span class="c"># look for data provider functions</span>  
        <span class="k">for</span> <span class="n">attrName</span><span class="p">,</span> <span class="n">attr</span> <span class="ow">in</span> <span class="n">classDict</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>  
            <span class="k">if</span> <span class="n">attrName</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s">"dataprovider_"</span><span class="p">):</span>  
                <span class="c"># find out the corresponding test method</span>  
                <span class="n">testName</span> <span class="o">=</span> <span class="n">attrName</span><span class="p">[</span><span class="mi">13</span><span class="p">:]</span>  
                <span class="n">testFunc</span> <span class="o">=</span> <span class="n">classDict</span><span class="p">[</span><span class="n">testName</span><span class="p">]</span>  
<span class="c"># the test method is no longer needed</span>  
                <span class="k">del</span> <span class="n">classDict</span><span class="p">[</span><span class="n">testName</span><span class="p">]</span>  
  
                <span class="c"># generate test method variants based on</span>  
                <span class="c"># data from the data porovider function</span>  
                <span class="n">i</span> <span class="o">=</span> <span class="mi">1</span>  
                <span class="k">for</span> <span class="n">args</span> <span class="ow">in</span> <span class="n">attr</span><span class="p">():</span>  
                    <span class="n">classDict</span><span class="p">[</span><span class="n">testName</span> <span class="o">+</span> <span class="nb">str</span><span class="p">(</span><span class="n">i</span><span class="p">)]</span> <span class="o">=</span> <span class="n">create_test_method</span><span class="p">(</span><span class="n">testFunc</span><span class="p">,</span> <span class="n">args</span><span class="p">)</span>  
                    <span class="n">i</span> <span class="o">+=</span> <span class="mi">1</span>  
  
        <span class="c"># create the type</span>  
        <span class="k">return</span> <span class="nb">type</span><span class="o">.</span><span class="n">__new__</span><span class="p">(</span><span class="n">meta</span><span class="p">,</span> <span class="n">classname</span><span class="p">,</span> <span class="n">bases</span><span class="p">,</span> <span class="n">classDict</span><span class="p">)</span>  

　　

这里其实用到了元类的概念，也就是，我们重写的type元类的__new__函数

验证一下：

class TestStringLength(unittest.TestCase):  
    __metaclass__ = DataProviderSupport  
  
    def dataprovider_test_len_function(): # no self!  
        yield ("abc", 3)  
        yield ("", 0)  
        yield ("a", 1)  
  
    def test_len_function(self, astring, expectedLength):  
        self.assertEqual(expectedLength, len(astring))  

　　运行 python的unittest，结果如下：

元类的概念，请参考：

http://www.ibm.com/developerworks/cn/linux/l-pymeta/

http://blog.csdn.net/b2b160/article/details/4161189

这个函数能够返回当前类的类名称，类字典，同时可以创建测试方法 即 create_test_method

当有多个测试数据对应一个测试方法时，我们把测试方法增加了序号，如果在后续引用测试方法时，需要在测试方法名称后面添加序号

例如 suite.addTest(Testdriver(methodname+sn))

 http://www.cnblogs.com/fnng/p/8185172.html