Add TopLevel#closest_window to pass failing test #508

	# This workflow uses actions that are not certified by GitHub.
	# They are provided by a third-party and are governed by
	# separate terms of service, privacy policy, and support
	# documentation.
	# This workflow will download a prebuilt Ruby version, install dependencies and run tests with Rake
	# For more information see: https://github.com/marketplace/actions/setup-ruby-jruby-and-truffleruby

	name: Ruby

	on:
	push:
	branches: [ master, development ]
	pull_request:
	branches: [ master ]

	jobs:
	test:

	runs-on: macos-latest

	steps:
	- uses: actions/checkout@v2
	- name: Install ActiveTcl
	run: mkdir tmp; curl -L https://www.dropbox.com/s/hel9o18x2b0j1m3/ActiveTcl-8.6.9.8609.2-macosx10.9-x86_64-93b04018.pkg?dl=1 > tmp/ActiveTcl.pkg; sudo installer -pkg tmp/ActiveTcl.pkg -target / -verbose
	- name: Set up Ruby
	# To automatically get bug fixes and new Ruby versions for ruby/setup-ruby,
	# change this to (see https://github.com/ruby/setup-ruby#versioning):
	# uses: ruby/setup-ruby@v1
	uses: ruby/setup-ruby@21351ecc0a7c196081abca5dc55b08f085efe09a
	with:
	bundler-cache: true
	ruby-version: 2.6
	- name: Install dependencies
	run: bundle install
	- name: Run tests
	run: bundle exec rake

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