t.Fatal(err)
	}
	defer RemoveAll(tempDir)
	filename := filepath.Join(tempDir, "blurp.txt")

	shmorp := []byte("shmorp")
	florp := []byte("florp")
	err = WriteFile(filename, shmorp, 0444)
	if err != nil {
		t.Fatalf("WriteFile %s: %v", filename, err)
	}
	err = WriteFile(filename, florp, 0444)
	if err == nil {
		t.Fatalf("Expected an error when writing to read-only file %s", filename)
	}
	got, err := ReadFile(filename)