This lib contains both standard imports and imports shuttle. Shuttle is a Rust crate that facilitates multithreaded testing. It has its own scheduler and can efficiently detect bugs in concurrent code. The downside is that we need to replace all imports by those from Shuttle.
Instead of importing from std, rand, and so on, import the following from solana-type-override, and include the 'shuttle-test' feature in your crate to use shuttle.