Add unit test for LdapBackendGroupProvider

tests/units/Group/LdapBackendGroupProviderTest.php

@@ -0,0 +1,16 @@
+<?php
+
+require_once __DIR__.'/../Base.php';
+
+use Kanboard\Group\LdapBackendGroupProvider;
+
+class LdapBackendGroupProviderTest extends Base
+{
+    public function testGetLdapGroupPattern()
+    {
+        $this->setExpectedException('LogicException', 'LDAP group filter empty, check the parameter LDAP_GROUP_FILTER');
+
+        $backend = new LdapBackendGroupProvider($this->container);
+        $backend->getLdapGroupPattern('test');
+    }
+}