Substrate & Ink
To interact with Polkadot, there are three envisioned development trajectories; a parachain implements it’s own runtime logic (think custom sidechain), a parathread is similar but only produces a block when absolutely necessary to update the relay chain, and a smart contract can run atop any chain with the correct execution environment. Substrate enables the former methodology based on a modular architecture with pluggable consensus and Parity maintain an embedded Domain Specific Language (eDSL) atop Substrate for WASM smart contracts.
Table Driven Tests
One of my favorite ways to write tests in Go is with a table driven test. If you are unfamiliar with the concept check out the excellent Dave Cheney post. If you need to unit test a component under a multitude of edge cases, then this is good technique to adopt. Anyway, I’m learning Rust in my spare time so I thought I’d best give it a go. Hopefully this will suffice, but if you think it could be improved please hit me up on twitter.