# Objective
To test systems that implement frame rate-independent update logic, one needs to be able to mock `Time`. By mocking time, it's possible to write tests that confirm systems are frame rate-independent.
This is a follow-up PR to #2549 by @ostwilkens and based on his work.
## Solution
To mock `Time`, one needs to be able to manually update the Time resource with an `Instant` defined by the developer. This can be achieved by making the existing `Time::update_with_instant` method public for use in tests.
## Changelog
- Make `Time::update_with_instant` public
- Add doc to `Time::update_with_instant` clarifying that the method should not be called outside of tests.
- Add doc test to `Time` demonstrating how to use `update_with_instant` in tests.
Co-authored-by: Martin Dickopp <martin@zero-based.org>
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