Add tests workflow

.github/workflows/tests.yml

@@ -0,0 +1,52 @@
+name: Tests
+
+on:
+  pull_request:
+    branches:
+      - main
+    paths-ignore:
+      - 'README.md'
+      - 'CHANGELOG.md'
+  push:
+    branches:
+      - main
+    paths-ignore:
+      - 'README.md'
+      - 'CHANGELOG.md'
+
+jobs:
+  unit_tests:
+    name: Unit Tests
+    # Homemade support for [ci skip] no longer needed
+    # https://github.blog/changelog/2021-02-08-github-actions-skip-pull-request-and-push-workflows-with-skip-ci/
+    # if: "contains(github.event.commits[0].message, '[ci skip]') == false"
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        ruby:
+          - "3.0"
+          - "3.1"
+          - "3.2"
+          - "3.3"
+        allow_failures:
+          - false
+        include:
+          - os: ubuntu-latest
+            ruby: "ruby-head"
+            allow_failures: true
+    env:
+      ALLOW_FAILURES: "${{ matrix.allow_failures }}"
+    runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ endsWith(matrix.ruby, 'head') || matrix.ruby == 'debug' }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - name: Test
+        run: bundle exec rake spec || $ALLOW_FAILURES