Fix negative step warning in slice test #408

	name: CI
	on: [push, pull_request]

	jobs:
	test:
	# cannot use latest to check older OTP versions, see:
	# https://github.com/erlef/setup-beam/issues/161#issuecomment-1336129218
	runs-on: ubuntu-20.04
	name: OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
	strategy:
	matrix:
	include:
	- elixir: "1.10"
	otp: "21.3"
	- elixir: "1.11"
	otp: "23.3"
	- elixir: "1.14"
	otp: "25.3"
	- elixir: "1.15"
	otp: "26.0"
	- elixir: "1.16"
	otp: "26.2"
	steps:
	- uses: actions/checkout@v2
	- uses: erlef/setup-beam@v1
	with:
	otp-version: ${{matrix.otp}}
	elixir-version: ${{matrix.elixir}}
	- name: Install Dependencies
	run: mix deps.get
	- name: Check compile warnings
	run: mix compile --warnings-as-errors
	# TODO add dialyzer?
	- name: Unit tests
	run: mix test.unit
	- name: Property-based tests
	run: PROP_TEST_RUNTIME=30000 mix test.prop

	format:
	runs-on: ubuntu-latest
	name: Format (Elixir ${{matrix.elixir}})
	strategy:
	matrix:
	include:
	- elixir: "1.16"
	otp: "26.2"
	steps:
	- uses: actions/checkout@v2
	- uses: erlef/setup-beam@v1
	with:
	otp-version: ${{matrix.otp}}
	elixir-version: ${{matrix.elixir}}
	- name: Install Dependencies
	run: mix deps.get
	- name: Check format
	run: mix format --check-formatted

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