diff --git a/tempest/common/identity.py b/tempest/common/identity.py
index 303f620..2179363 100644
--- a/tempest/common/identity.py
+++ b/tempest/common/identity.py
@@ -22,3 +22,11 @@
         if tenant['name'] == tenant_name:
             return tenant
     raise lib_exc.NotFound('No such tenant(%s) in %s' % (tenant_name, tenants))
+
+
+def get_user_by_username(client, tenant_id, username):
+    users = client.list_tenant_users(tenant_id)['users']
+    for user in users:
+        if user['name'] == username:
+            return user
+    raise lib_exc.NotFound('No such user(%s) in %s' % (username, users))