feat: parallelise unit tests

.github/workflows/test-unit.yaml

@@ -14,8 +14,36 @@ env:
 
 jobs:
 
+  generate-packages:
+    name: List Go Packages
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Go ${{ env.GO_VERSION }}
+        uses: actions/setup-go@v5
+        with:
+          go-version: ${{ env.GO_VERSION }}
+          check-latest: true
+
+      - name: Generate matrix
+        id: set-matrix
+        run: |
+          matrix_output=$(go run ./internal/testsci/genmatrix.go)
+          echo "$matrix_output"
+          echo "$matrix_output" >> $GITHUB_OUTPUT
+
   test-unit:
     runs-on: ubuntu-latest
+    needs: generate-packages
+    strategy:
+      matrix:
+        package: ${{ fromJson(needs.generate-packages.outputs.matrix) }}
 
     steps:
       - name: Check out code
@@ -33,7 +61,8 @@ jobs:
         run: touch webui/static/index.html
 
       - name: Tests
-        run: make test-unit
+        run: |
+          go test -v -parallel 8 ${{ matrix.package.group }}
 
   test-ui-unit:
     runs-on: ubuntu-latest

internal/testsci/genmatrix.go

@@ -0,0 +1,66 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/traefik/traefik/v2/pkg/log"
+	"golang.org/x/tools/go/packages"
+)
+
+const groupCount = 12
+
+type group struct {
+	Group string `json:"group"`
+}
+
+func main() {
+	logger := log.WithoutContext()
+
+	cfg := &packages.Config{
+		Mode: packages.NeedName,
+		Dir:  ".",
+	}
+
+	pkgs, err := packages.Load(cfg, "./cmd/...", "./pkg/...")
+	if err != nil {
+		logger.Fatalf("Loading packages: %v", err)
+	}
+
+	var packageNames []string
+	for _, pkg := range pkgs {
+		if pkg.PkgPath != "" {
+			packageNames = append(packageNames, pkg.PkgPath)
+		}
+	}
+
+	total := len(packageNames)
+	perGroup := (total + groupCount - 1) / groupCount
+
+	fmt.Fprintf(os.Stderr, "Total packages: %d\n", total)
+	fmt.Fprintf(os.Stderr, "Packages per group: %d\n", perGroup)
+
+	var matrix []group
+	for i := range groupCount {
+		start := i * perGroup
+		end := start + perGroup
+		if start >= total {
+			break
+		}
+		if end > total {
+			end = total
+		}
+		g := strings.Join(packageNames[start:end], " ")
+		matrix = append(matrix, group{Group: g})
+	}
+
+	jsonBytes, err := json.Marshal(matrix)
+	if err != nil {
+		logger.Fatalf("Failed to marshal matrix: %v", err)
+	}
+
+	// Output for GitHub Actions
+	fmt.Printf("matrix=%s\n", string(jsonBytes))
+}