Close out the repository audit

internal/testutil/symlink.go

@@ -0,0 +1,26 @@
+// Package testutil contains test-only helpers shared across package suites.
+package testutil
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"testing"
+)
+
+// RequireSymlink creates a symbolic link or skips when the host explicitly
+// reports that the operation is unsupported or unavailable to the test user.
+// Unexpected setup failures remain test failures.
+func RequireSymlink(t testing.TB, target, link string) {
+	t.Helper()
+	if err := os.Symlink(target, link); err != nil {
+		if symlinkUnavailable(err) {
+			t.Skipf("symlink support is unavailable: %v", err)
+		}
+		t.Fatalf("create symlink %q -> %q: %v", link, target, err)
+	}
+}
+
+func symlinkUnavailable(err error) bool {
+	return errors.Is(err, fs.ErrPermission) || errors.Is(err, errors.ErrUnsupported) || platformSymlinkUnavailable(err)
+}

internal/testutil/symlink_other.go

@@ -0,0 +1,7 @@
+//go:build !windows
+
+package testutil
+
+func platformSymlinkUnavailable(error) bool {
+	return false
+}

internal/testutil/symlink_test.go

@@ -0,0 +1,25 @@
+package testutil
+
+import (
+	"errors"
+	"io/fs"
+	"testing"
+)
+
+func TestSymlinkUnavailableClassifiesOnlyCapabilityErrors(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		err  error
+		want bool
+	}{
+		{name: "permission", err: fs.ErrPermission, want: true},
+		{name: "unsupported", err: errors.ErrUnsupported, want: true},
+		{name: "unexpected", err: errors.New("fixture path is invalid"), want: false},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			if got := symlinkUnavailable(test.err); got != test.want {
+				t.Fatalf("symlinkUnavailable(%v) = %t, want %t", test.err, got, test.want)
+			}
+		})
+	}
+}

internal/testutil/symlink_windows.go

@@ -0,0 +1,12 @@
+//go:build windows
+
+package testutil
+
+import (
+	"errors"
+	"syscall"
+)
+
+func platformSymlinkUnavailable(err error) bool {
+	return errors.Is(err, syscall.ERROR_PRIVILEGE_NOT_HELD)
+}