teraWeb/backend/internal/storage/atomicfile/file_test.go

package atomicfile

import (
	"os"
	"path/filepath"
	"runtime"
	"testing"
)

func TestWriteAtomicallyReplacesProtectedFile(t *testing.T) {
	path := filepath.Join(t.TempDir(), "state.json")
	if err := os.WriteFile(path, []byte("old"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := Write(path, []byte("new\n"), 0o600); err != nil {
		t.Fatalf("Write() error = %v", err)
	}
	content, err := os.ReadFile(path)
	if err != nil || string(content) != "new\n" {
		t.Fatalf("content = %q, %v", content, err)
	}
	if runtime.GOOS != "windows" {
		info, err := os.Stat(path)
		if err != nil {
			t.Fatal(err)
		}
		if got := info.Mode().Perm(); got != 0o600 {
			t.Fatalf("mode = %o, want 600", got)
		}
	}
	matches, err := filepath.Glob(filepath.Join(filepath.Dir(path), ".tera-store-*"))
	if err != nil || len(matches) != 0 {
		t.Fatalf("temporary files = %v, %v", matches, err)
	}
}

func TestWriteRefusesNonRegularDestination(t *testing.T) {
	path := filepath.Join(t.TempDir(), "state")
	if err := os.Mkdir(path, 0o700); err != nil {
		t.Fatal(err)
	}
	if err := Write(path, []byte("new"), 0o600); err == nil {
		t.Fatal("Write() replaced a directory")
	}
}

func TestWriteRefusesSymbolicLinkDestination(t *testing.T) {
	root := t.TempDir()
	target := filepath.Join(root, "target.json")
	link := filepath.Join(root, "state.json")
	if err := os.WriteFile(target, []byte("preserve"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.Symlink(target, link); err != nil {
		t.Skipf("symbolic links unavailable: %v", err)
	}
	if err := Write(link, []byte("replace"), 0o600); err == nil {
		t.Fatal("Write() followed a symbolic link")
	}
	content, err := os.ReadFile(target)
	if err != nil || string(content) != "preserve" {
		t.Fatalf("target content = %q, %v", content, err)
	}
}