CI: format, cross-platform vet, staticcheck, tests, race, examples

.github/workflows/ci.yml

@@ -0,0 +1,59 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  test:
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 30
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { name: macOS, os: macos-latest, skip: "" }
+          # Snapshot goldens exist only for darwin; see docs/compat.md.
+          - { name: Linux, os: ubuntu-latest, skip: "-skip Snapshot" }
+          - { name: Windows, os: windows-latest, skip: "-skip Snapshot" }
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-go@v6
+        with:
+          go-version-file: go.mod
+      - name: Format
+        if: runner.os == 'Linux'
+        run: test -z "$(gofmt -l .)" || { gofmt -l .; exit 1; }
+      - name: Build and vet every platform
+        if: runner.os == 'Linux'
+        run: |
+          for os in darwin linux windows; do
+            GOOS=$os go build ./...
+            GOOS=$os go vet ./...
+          done
+      - name: Staticcheck
+        if: runner.os == 'Linux'
+        run: go run honnef.co/go/tools/cmd/staticcheck@v0.8.1 ./...
+      - name: Test
+        run: go test ${{ matrix.skip }} ./...
+      - name: Race
+        if: runner.os != 'Windows'
+        run: go test -race ${{ matrix.skip }} ./...
+      - name: Examples compile
+        run: go build ./examples/...
+      - name: Upload snapshot diffs
+        if: failure()
+        uses: actions/upload-artifact@v5
+        with:
+          name: snapshot-diffs-${{ matrix.name }}
+          path: testdata/snapshots/**/*.got.png
+          if-no-files-found: ignore