模拟Wordpress单元测试

The function I'm testing requires another plugin, but I want to test it in isolation without having that plugin activated.

function functionName() {
   ...
   if (!is_plugin_active('path/to/plugin.php')) {
      return false;
   }
   return true;
}

How can I simulate that call returning true when I write a unit test?

You can modify the 'active_plugins' option during your tests to include that plugin.