create SQL function "change_user_password"

src/test/sql/user.sql

@@ -2,6 +2,7 @@ do
 $$
 declare
     created_user json := '{"username": "george", "plain_password": "azerty", "roles": ["ROLE_USER"]}';
+    user_with_other_password json;
     selected_user json;
     exist_user json;
 begin
@@ -24,6 +25,12 @@ begin
     assert exist_user->>'username' = 'george', format('the function check_user must be return user object with username is "george", %s is return', exist_user::text);
     assert exist_user->>'password' is null, format('the function check_user must not be return the password, %s is return', exist_user::text);
 
+    -- test change password
+    user_with_other_password = jsonb_set(created_user::jsonb, '{plain_password}', '"qwerty"'::jsonb);
+    perform change_user_password(user_with_other_password);
+    select check_user('george', 'qwerty') into exist_user;
+    assert exist_user->>'username' = 'george', format('the function change_user_password must change password: %s', exist_user::text);
+
     -- delete user and check if user is really not exists
     delete from "user" where username = 'george';
     select check_user('george', 'azerty') into exist_user;