diff --git a/src/Auth/Cas.php b/src/Auth/Cas.php
index 993eac3..07f695e 100644
--- a/src/Auth/Cas.php
+++ b/src/Auth/Cas.php
@@ -81,16 +81,21 @@ class Cas extends Method {
    * @return \EesyPHP\Auth\User|null
    */
   public static function login($force=false) {
-    if (!phpCAS :: isAuthenticated() && $force) {
-      $_SESSION['cas_callback_url'] = self :: get_cas_callback_url();
-      phpCAS :: setFixedServiceURL($_SESSION['cas_callback_url']);
-      phpCAS :: forceAuthentication();
+    if (self :: $fake_authenticated_user) {
+      $user = Auth :: get_user(self :: $fake_authenticated_user);
+    }
+    else {
+      if (!phpCAS :: isAuthenticated() && $force) {
+        $_SESSION['cas_callback_url'] = self :: get_cas_callback_url();
+        phpCAS :: setFixedServiceURL($_SESSION['cas_callback_url']);
+        phpCAS :: forceAuthentication();
+      }
+      $user = (
+        phpCAS :: isAuthenticated()?
+        Auth :: get_user(phpCAS :: getUser()):
+        null
+      );
     }
-    $user = (
-      phpCAS :: isAuthenticated()?
-      Auth :: get_user(phpCAS :: getUser()):
-      null
-    );
     if ($force && !$user)
       Log :: fatal('Fail to authenticate you');
     return $user;