diff --git a/src/keycloak/keycloak_admin.py b/src/keycloak/keycloak_admin.py
index e740ce1..8ee275a 100644
--- a/src/keycloak/keycloak_admin.py
+++ b/src/keycloak/keycloak_admin.py
@@ -88,7 +88,7 @@ class KeycloakAdmin:
 
     def __init__(
         self,
-        server_url,
+        server_url=None,
         username=None,
         password=None,
         token=None,
diff --git a/tests/test_keycloak_admin.py b/tests/test_keycloak_admin.py
index e984023..454acfc 100644
--- a/tests/test_keycloak_admin.py
+++ b/tests/test_keycloak_admin.py
@@ -9,7 +9,7 @@ import pytest
 from dateutil import parser as datetime_parser
 
 import keycloak
-from keycloak import KeycloakAdmin, KeycloakOpenID
+from keycloak import KeycloakAdmin, KeycloakOpenID, KeycloakOpenIDConnection
 from keycloak.connection import ConnectionManager
 from keycloak.exceptions import (
     KeycloakAuthenticationError,
@@ -111,6 +111,17 @@ def test_keycloak_admin_init(env):
         is None
     )
 
+    keycloak_connection = KeycloakOpenIDConnection(
+        server_url=f"http://{env.KEYCLOAK_HOST}:{env.KEYCLOAK_PORT}",
+        username=env.KEYCLOAK_ADMIN,
+        password=env.KEYCLOAK_ADMIN_PASSWORD,
+        realm_name="master",
+        client_id="admin-cli",
+        verify=True,
+    )
+    keycloak_admin = KeycloakAdmin(connection=keycloak_connection)
+    assert keycloak_admin.token
+
 
 def test_realms(admin: KeycloakAdmin):
     """Test realms.