t.Errorf("i=%d: ModTime: got %v, want %v", i, got, want)
		}
		if sysh, ok := fi.Sys().(*Header); !ok || sysh != v.h {
			t.Errorf("i=%d: Sys didn't return original *Header", i)
		}
	}
}

func TestHeaderAllowedFormats(t *testing.T) {
	vectors := []struct {
		header  *Header           // Input header
		paxHdrs map[string]string // Expected PAX headers that may be needed