初版功能完成

internal/platform/windows/wintunruntime/runtime_windows_test.go

@@ -0,0 +1,86 @@
+//go:build windows && amd64
+
+package wintunruntime
+
+import (
+	"os"
+	"path/filepath"
+	"sync"
+	"testing"
+)
+
+func TestInstallIsVerifiedIdempotentAndRepairsUnexpectedFile(t *testing.T) {
+	root := t.TempDir()
+	path, err := Install(root)
+	if err != nil {
+		t.Fatalf("Install() error = %v", err)
+	}
+	if got, want := path, filepath.Join(root, DLLName); got != want {
+		t.Fatalf("Install() path = %q, want %q", got, want)
+	}
+	first, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile() error = %v", err)
+	}
+
+	secondPath, err := Install(root)
+	if err != nil {
+		t.Fatalf("second Install() error = %v", err)
+	}
+	if secondPath != path {
+		t.Fatalf("second Install() path = %q, want %q", secondPath, path)
+	}
+
+	if err := os.WriteFile(path, []byte("tampered"), 0o644); err != nil {
+		t.Fatalf("tamper DLL: %v", err)
+	}
+	if _, err := Install(root); err != nil {
+		t.Fatalf("repair Install() error = %v", err)
+	}
+	repaired, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read repaired DLL: %v", err)
+	}
+	if string(repaired) != string(first) {
+		t.Fatal("Install() did not repair the unexpected DLL")
+	}
+}
+
+func TestInstallPublishesAtomicallyAcrossConcurrentProcesses(t *testing.T) {
+	root := t.TempDir()
+	target := filepath.Join(root, DLLName)
+	if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(target, []byte("corrupt"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	const workers = 16
+	errorsByWorker := make([]error, workers)
+	paths := make([]string, workers)
+	var wait sync.WaitGroup
+	for index := 0; index < workers; index++ {
+		wait.Add(1)
+		go func(index int) {
+			defer wait.Done()
+			paths[index], errorsByWorker[index] = Install(root)
+		}(index)
+	}
+	wait.Wait()
+	for index := range errorsByWorker {
+		if errorsByWorker[index] != nil || paths[index] != target {
+			t.Fatalf("worker %d path=%q error=%v", index, paths[index], errorsByWorker[index])
+		}
+	}
+	data, expected, err := assetBytes()
+	if err != nil {
+		t.Fatal(err)
+	}
+	installed, err := os.ReadFile(target)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(installed) != string(data) {
+		t.Fatalf("concurrent install produced %d bytes, want %d (expected hash %x)", len(installed), len(data), expected)
+	}
+}