CI: Register github action

.github/workflows/tests.yml

@@ -0,0 +1,58 @@
+# 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: CI
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: "test on ${{ matrix.os }} ; ${{ matrix.neovim && 'neovim' || 'vim' }}"
+
+    strategy:
+      matrix:
+        # Testing doesn't seem to work on Windows: output log file
+        # cannot be read...
+        # os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest, macos-latest]
+        neovim: [false, true]
+        # TODO: Test different flavours of Vim...
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 3.0
+        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+    - name: Setup Vim
+      uses: rhysd/action-setup-vim@v1
+      # uses: thinca/action-setup-vim@v2
+      id: vim
+      with:
+        neovim: ${{matrix.neovim }}
+        configure-args: |
+          --with-features=huge
+
+    - name: Run tests on Linux
+      if: runner.os == 'Linux' # headless execution is required on Linux
+      run: |
+        xvfb-run bundle exec rake ci
+    - name: Run tests on ${{ matrix.os }}
+      if: runner.os != 'Linux'
+      run: |
+        bundle exec rake ci
+