title: Java - Unit Test
body: <p>Given this method in a Java class: </p>
  
  <pre><code>public void execute(String command) {
  
      ProcessBuilder processBuilder = new ProcessBuilder(command);
      Process process = processBuilder.start();
  
      int exitValue = process.waitFor();
      if (exitValue != 0) {
          throw new RuntimeException("a message here...");
      }
  }
  </code></pre>
  
  <p>I'm trying to come up with a proper <strong>cross platform</strong> unit test for this method.</p>
  
  <p>I'm looking for a common command across all operating systems (Win, Linux, Mac and ...) or a fake command that I can pass to this method in my unit tests.</p>
  
  <p>Any suggestion ? </p>