implement callback for headless instance #127

	name: Test osv
	on: [push, pull_request]
	jobs:
	Test-osv:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	neovim_version: ['nightly', 'stable', 'v0.9.0', 'v0.10.0']
	steps:
	- name: Check out repository code
	uses: actions/checkout@v2
	- run: date +%F > todays-date
	- name: Restore cache for today's nightly
	uses: actions/cache@v2
	with:
	path: _neovim
	key: ${{ runner.os }}-x64-${{ hashFiles('todays-date') }}
	- name: Setup neovim
	uses: rhysd/action-setup-vim@v1
	with:
	neovim: true
	version: ${{ matrix.neovim_version }}
	- name: Prepare
	run: \|
	mkdir -p ~/.local/share/nvim/site/pack/vendor/start
	git clone --depth 1 https://github.com/mfussenegger/nvim-dap ~/.local/share/nvim/site/pack/vendor/start/nvim-dap
	git clone --depth 1 https://github.com/jbyuki/one-small-step-for-vimkind ~/.local/share/nvim/site/pack/vendor/start/one-small-step-for-vimkind
	- name: List files in the repository
	run: \|
	ls ${{ github.workspace }}
	- name: Run tests
	run: \|
	cp test/input.lua input.lua
	cat input.lua
	cat test/test.lua
	nvim --headless -c "luafile test/test.lua" -c "exit"
	echo "Done"
	cat result.txt

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