build: run unit tests on push and PRs

.github/workflows/tests.yml

@@ -0,0 +1,55 @@
+# From
+# https://github.com/shortcuts/neovim-plugin-boilerplate/blob/main/.github/workflows/main.yml
+
+name: tests
+
+on:
+  push:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    name: lint
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: JohnnyMorganz/stylua-action@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          version: latest
+          args: --check . -g '*.lua' -g '!deps/'
+
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    strategy:
+      matrix:
+        neovim_version: ["v0.7.2", "v0.8.3", "v0.9.5", "v0.10.0", "nightly"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - run: date +%F > todays-date
+
+      - name: restore cache for today's nightly.
+        uses: actions/cache@v4
+        with:
+          path: _neovim
+          key: ${{ runner.os }}-x64-${{ hashFiles('todays-date') }}
+
+      - name: setup neovim
+        uses: rhysd/action-setup-vim@v1
+        with:
+          neovim: true
+          version: ${{ matrix.neovim_version }}
+
+      - name: install ripgrep
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y ripgrep
+
+      - name: run tests
+        run: |
+          make test