home-assistant: convert tests to pytestCheckHook
home-assistant: convert tests to pytestCheckHook

Enables testing in parallel. This cuts down the test phase from over
five to under one minute on my 6C/12T processor.

Sadly while the upstream runs their tests using `-n auto` this isn't
working for us in all cases. I currently assume they use low concurrency in
their CI, which is not triggering these issues..

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs