t.Errorf("WriteHeader() = got %v, want non-nil error", err)
		}
		if _, err := tw.Write(nil); err == nil {
			t.Errorf("Write() = %v, want non-nil error", err)
		}
		if err := tw.Flush(); err == nil {
			t.Errorf("Flush() = %v, want non-nil error", err)
		}
		if err := tw.Close(); err == nil {
			t.Errorf("Close() = %v, want non-nil error", err)
		}
	})
}

		t.Fatalf("unexpected CreateHeader error: %v", err)
	}
	if err := w.Close(); err != nil {
		t.Fatalf("unexpected Close error: %v", err)
	}

	want, err := os.ReadFile("testdata/time-go.zip")
	if err != nil {
		t.Fatalf("unexpected ReadFile error: %v", err)
	}
	if got := buf.Bytes(); !bytes.Equal(got, want) {
		fmt.Printf("%x\n%x\n", got, want)
		t.Error("contents of time-go.zip differ")
	}
}