Codeception - custom test $params for Functional Tests

I want to set custom $params for Functional Tests. I cannot see where codeception allows defining custom params for tests. How can I define a custom params for testing?

What do you mean by custom params? Where/how do you want to set these and how do you want to use these?

I am referring to

$params = array_merge(
    require __DIR__ . '/../../common/config/params.php',
    require __DIR__ . '/../../common/config/params-local.php',
    require __DIR__ . '/params.php',
    require __DIR__ . '/params-local.php'

defined in frontend/config/main.php

For e.g. there is a user.passwordResetTokenExpire set to 3600 - In the automated testing I would like to set this to a low number so I may test it without having to actually wait that long. This is just an example I have few other parameters like these I want to set to different values for testing.