Port Printer from graphql-js #190

	name: Tests

	on:
	push:
	branches: [ main ]
	paths-ignore: [ README.md ]
	pull_request:
	branches: [ main ]
	paths-ignore: [ README.md ]
	workflow_dispatch:

	jobs:
	formatlint:
	name: Lint for correct formatting
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v3
	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v2
	- name: Pull formatting docker image
	run: docker pull ghcr.io/nicklockwood/swiftformat:latest
	- name: Run format linting
	run: docker run --rm -v ${{ github.workspace }}:/repo ghcr.io/nicklockwood/swiftformat:latest /repo --lint

	macos:
	name: Build and test on macos-latest
	runs-on: macos-latest
	steps:
	- uses: swift-actions/setup-swift@v1
	- uses: actions/checkout@v3
	- name: Test
	run: swift test

	# ubuntu-latest is ubuntu-22.04 currently. Swift versions older than 5.7 don't have builds for 22.04. https://www.swift.org/download/
	ubuntu-old:
	name: Build ${{ matrix.swift }} on ${{ matrix.os }}
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os: [ubuntu-20.04]
	swift: ["5.5", "5.6"]
	steps:
	- uses: swift-actions/setup-swift@v1
	with:
	swift-version: ${{ matrix.swift }}
	- uses: actions/checkout@v3
	- name: Test
	run: swift test

	ubuntu-latest:
	name: Build ${{ matrix.swift }} on ${{ matrix.os }}
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os: [ubuntu-latest]
	swift: ["5.7", "5.8"]
	steps:
	- uses: swift-actions/setup-swift@v1
	with:
	swift-version: ${{ matrix.swift }}
	- uses: actions/checkout@v3
	- name: Test
	run: swift test

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