fix path handling in `action_url()`, fixes #1105

Closes #1105

Merge request studip/studip!661

app/controllers/studip_controller.php

@@ -717,7 +717,7 @@ abstract class StudipController extends Trails_Controller
     public function action_url($action)
     {
         $arguments = func_get_args();
-        array_unshift($arguments, $this->controller_path());
+        $arguments[0] = $this->controller_path() . '/' . $arguments[0];
 
         return $this->url_for(...$arguments);
     }

tests/unit/lib/classes/StudipControllerTest.php

@@ -65,6 +65,19 @@ final class StudipControllerTest extends Codeception\Test\Unit
         $this->getController()->url_for(...$args);
     }
 
+    /**
+     * @dataProvider actionUrlProvider
+     * @covers StudipController::action_url
+     */
+    public function testActionUrl(string $expected, ...$args): void
+    {
+        $url = $this->getController()->action_url(...$args);
+        $this->assertEquals(
+            $expected,
+            $this->getRelativeURL($url)
+        );
+    }
+
     /**
      * @dataProvider RedirectProvider
      * @covers StudipController::redirect
@@ -192,6 +205,19 @@ final class StudipControllerTest extends Codeception\Test\Unit
         ];
     }
 
+    public function actionUrlProvider(): array
+    {
+        return [
+            'action'                   => ['dispatch.php/studip_controller_test/foo', 'foo'],
+            'action-and-parameter'     => ['dispatch.php/studip_controller_test/foo/23', 'foo/23'],
+            'action-and-parameters'    => ['dispatch.php/studip_controller_test/foo/23?bar=42', 'foo/23', ['bar' => 42]],
+
+            'fragment'                 => ['dispatch.php/studip_controller_test/foo/42/23#jump', 'foo/42/23#jump'],
+            'fragment-and-parameters'  => ['dispatch.php/studip_controller_test/foo/42/23#jump', 'foo#jump', 42, 23],
+            'url-encoding-parameters'  => ['dispatch.php/studip_controller_test/foo/%3Fabc/%2F', 'foo', '?abc', '/'],
+        ];
+    }
+
     public function RedirectProvider(): array
     {
         $result = $this->UrlForProvider();