title: How to define and use a system property in Android Instrumentation test?
body: <p>I am trying to use some arguments for an Instrumentation test. I noticed that I can read system properties with <code>System.getProperty()</code> function. So I use setprop command to set a system property. For example: <code>adb shell setprop AP 123</code>.
  Inside my Test code I try to read this AP property with : </p>
  
  <pre><code>
  tmp = System.getProperty("AP"); 
  Log.d("MyTest","AP Value = " + tmp);
  </code></pre>
  
  <p>Then I use logcat to view this debug message but I get a null value for this property. Any ideas on what could be wrong? 
  Note that I can still read the system property with <code>adb shell getprop AP</code> command.</p>