Add test workflow

.github/workflows/test.yaml

@@ -0,0 +1,30 @@
+name: Run test
+
+on:
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby-version:
+        - 1.9.3
+        - 2.0.0
+        - 2.1.9
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby ${{ matrix.ruby-version }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+
+      - name: Install dependencies
+        run: bundle install
+
+      - name: Run tests
+        run: bundle exec rake