diff --git a/test/postgres-init.sql b/test/postgres-init.sql
index 029bff38..bab9dc84 100644
--- a/test/postgres-init.sql
+++ b/test/postgres-init.sql
@@ -72,7 +72,7 @@ UPDATE users SET manager_id = (SELECT id FROM users WHERE username = 'robert.tab
 -- Create roles table
 CREATE TABLE roles (
   id SERIAL PRIMARY KEY,
-  role_name VARCHAR(100) NOT NULL
+  role_name VARCHAR(100) NOT NULL UNIQUE
 );
 
 -- Insert sample roles