Fix Nix build, add more Nix usage docs, more relaxed Rust build artifacts discovery #21

	name: Tests

	on:
	pull_request:
	push:
	branches: ["master"]

	jobs:
	unit_tests:
	name: unit tests
	runs-on: ${{ matrix.os }}
	strategy:
	fail-fast: false
	matrix:
	include:
	- os: ubuntu-22.04
	rev: nightly/nvim-linux64.tar.gz
	# manager: sudo apt-get
	# packages: -y ripgrep
	- os: ubuntu-22.04
	rev: v0.9.0/nvim-linux64.tar.gz
	# manager: sudo apt-get
	# packages: -y ripgrep
	steps:
	- uses: actions/checkout@v3
	- run: date +%F > todays-date
	- name: Restore from todays cache
	uses: actions/cache@v3
	with:
	path: _neovim
	key: ${{ runner.os }}-${{ matrix.rev }}-${{ hashFiles('todays-date') }}

	- name: Cache rust items
	uses: actions/cache@v3
	with:
	path: \|
	~/.rustup/
	~/.cargo/bin/
	~/.cargo/registry/index/
	~/.cargo/registry/cache/
	~/.cargo/git/db/
	target/
	key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}

	- name: Build rust items
	run: \|
	cargo build --workspace --bins

	- name: Prepare
	run: \|
	# ${{ matrix.manager }} update
	# ${{ matrix.manager }} install ${{ matrix.packages }}
	test -d _neovim \|\| {
	mkdir -p _neovim
	curl -sL "https://github.com/neovim/neovim/releases/download/${{ matrix.rev }}" \| tar xzf - --strip-components=1 -C "${PWD}/_neovim"
	}
	mkdir -p ~/.local/share/nvim/site/pack/vendor/start
	git clone --depth 1 https://github.com/nvim-lua/plenary.nvim ~/.local/share/nvim/site/pack/vendor/start/plenary.nvim
	ln -s $(pwd) ~/.local/share/nvim/site/pack/vendor/start

	- name: Run tests
	run: \|
	export PATH="${PWD}/_neovim/bin:${PATH}"
	export VIM="${PWD}/_neovim/share/nvim/runtime"
	nvim --version
	make test

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