gha: add basic test

Test against the "oldest" supported version and the current version
of go. Go 1.17 is kept in this matrix as it is the minimum version
specified in go.mod, and maintaining compatibility with go 1.17 is
currently not much of a burden. Most projects using this module are
using newer versions than that, so we can drop the old version if
it becomes too much of a burden.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.github/workflows/test.yml

@@ -0,0 +1,45 @@
+name: test
+on:
+  push:
+    tags:
+      - v*
+    branches:
+      - master
+      - main
+  pull_request:
+    branches:
+      - master
+      - main
+
+jobs:
+  test:
+    permissions:
+      contents: read      # for actions/checkout to fetch code
+    timeout-minutes: 10
+
+    strategy:
+      matrix:
+        # test against the "oldest" supported version and the current version
+        # of go. Go 1.17 is kept in this matrix as it is the minimum version
+        # specified in go.mod, and maintaining compatibility with go 1.17 is
+        # currently not much of a burden. Most projects using this module are
+        # using newer versions than that, so we can drop the old version if
+        # it becomes too much of a burden.
+        go-version: [1.17.x, stable]
+        os: [ubuntu-20.04, ubuntu-22.04, windows-2022]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@v3
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Checkout code
+      uses: actions/checkout@v3
+    - name: go mod tidy
+      run: |
+        go mod tidy
+        git diff --exit-code
+    - name: Test
+      run: |
+        go test -exec "sudo -n" -v ./...
+