diff --git a/Tests/dblayerooComplet.php b/Tests/dblayerooComplet.php
index 627098d..38639bd 100644
--- a/Tests/dblayerooComplet.php
+++ b/Tests/dblayerooComplet.php
@@ -550,6 +550,7 @@ class test_dblayeroo_{ENGINE} extends PHPUnit_Framework_TestCase
                ->displayAdd ("group")
                ->joinLeft ($tbl2, array ("group"=>"group"))
                ->orderAdd ("group", "ASC")
+->debug (1)
                ->execute ();
     $tbl1->disconnect ();
     $tbl2->disconnect ();
@@ -930,8 +931,30 @@ class test_dblayeroo_{ENGINE} extends PHPUnit_Framework_TestCase
     $tbl1 = $this->tbl1 ();
     $tbl1->displayAdd ("group_concat (group ),group ",
                        "Group Alias,Group2");
+    // PGSQL generate an exception :
+    // function string_agg(character varying) does not exist
+    if ($this->engine === "pgsql")
+      $this->setExpectedException ("PDOException");
     $res = $tbl1->select ()
                 ->execute ();
     $tbl1->disconnect ();
+    if ($this->engine !== "pgsql")
+      $this->assertSame (array (
+        array ('Group Alias' => 'group1',
+               'Group2' => 'group1',),
+        array ('Group Alias' => 'group2',
+               'Group2' => 'group2',),
+      ), $res);
+  }
+
+  public function test_displayAdd_DISTINCT1 ()
+  {
+    $tbl1 = $this->tbl1 ();
+    $res = $tbl1->select ()
+                ->displayAdd ("distinct where", "ALIAS")
+                ->execute ();
+    $tbl1->disconnect ();
+    $this->assertSame (array (0=>array ("ALIAS"=>"where2")),
+                       $res);
   }
 }