TtlCache and testing

[vi]

As far as I undestand, TtlCache use std::time::{Duration, Instant} without any indirection layer.

This makes it trickier to [unit-]test the code without waiting.

Shall there be some additional testing version of TtlCache that has overridable timer?

[stusmall]

Great point. I'll look into doing this. Do you have any thoughts on what you would like the general API to look like?

[stusmall]

I was thinking about this. I think I might implement this as a generic type parameter. By default it will be an implementation that directly calls Duration/Instant but a user may optionally implement a struct that can mock it out.

Before I make my own trait, do you know of any good crates that define the abstraction? I'd rather just pull in something other people are already using.

[lerouxrgd]

I usually find that fake_clock is a nice solution if you can apply it to your use-case.

This blog post is a good example of it.