c# – 如何测试方法(白盒测试)

private static void selectTop20Tags(Dictionary<string,int> list)
    {

         //Outputs the top 20 most common hashtags in descending order
         foreach (KeyValuePair<string,int> pair in list.OrderByDescending(key => key.Value).Take(20))
         {
             Console.WriteLine("{0},{1}",pair.Key,pair.Value);
         }

    }

我不知道我将如何测试这一点,我一直在研究它并尝试各种各样的东西,但无法让它工作.

我想要包括一些代码,比如

#if TEST
            if ((length of list don't know how you would do it) <= 20)
            {
                StreamWriter log2;
                // appends file
                log2 = File.AppendText("logOfTests.txt");
                // Writes to the file
                log2.WriteLine("PASS");
                log2.WriteLine();

                // Closes the stream
                log2.Close();
            }
#endif

我想我只需要看一个例子,我就会知道.