diff --git a/group/tests/externallib_test.php b/group/tests/externallib_test.php
index dcbb0ef2742..fff4079f1e7 100644
--- a/group/tests/externallib_test.php
+++ b/group/tests/externallib_test.php
@@ -106,9 +106,8 @@ class core_group_externallib_testcase extends externallib_advanced_testcase {
             $froups = core_group_external::create_groups(array($group3));
             $this->fail('Exception expected due to already existing idnumber.');
         } catch (moodle_exception $e) {
-            $this->assertInstanceOf('invalid_parameter_exception', $e);
-            $this->assertEquals('Invalid parameter value detected (Group with the same idnumber already exists)',
-                $e->getMessage());
+            $this->assertInstanceOf('moodle_exception', $e);
+            $this->assertEquals(get_string('idnumbertaken', 'error'), $e->getMessage());
         }
 
         // Call without required capability
@@ -258,9 +257,8 @@ class core_group_externallib_testcase extends externallib_advanced_testcase {
             $groupings = core_group_external::create_groupings(array($grouping1data));
             $this->fail('Exception expected due to already existing idnumber.');
         } catch (moodle_exception $e) {
-            $this->assertInstanceOf('invalid_parameter_exception', $e);
-            $this->assertEquals('Invalid parameter value detected (Grouping with the same idnumber already exists)',
-                $e->getMessage());
+            $this->assertInstanceOf('moodle_exception', $e);
+            $this->assertEquals(get_string('idnumbertaken', 'error'), $e->getMessage());
         }
 
         // No exception should be triggered.
@@ -285,9 +283,8 @@ class core_group_externallib_testcase extends externallib_advanced_testcase {
             $groupings = core_group_external::update_groupings(array($grouping2data));
             $this->fail('Exception expected due to already existing idnumber.');
         } catch (moodle_exception $e) {
-            $this->assertInstanceOf('invalid_parameter_exception', $e);
-            $this->assertEquals('Invalid parameter value detected (A different grouping with the same idnumber already exists)',
-                $e->getMessage());
+            $this->assertInstanceOf('moodle_exception', $e);
+            $this->assertEquals(get_string('idnumbertaken', 'error'), $e->getMessage());
         }
     }